Cultured human fibroblasts and not cultured human keratinocytes express a PTH/PTHrP receptor mRNA

There is increasing evidence that parathyroid hormone (PTH) and PTH-related peptides (PTHrP) are involved in normal skin cell growth; therefore, we investigated whether the PTH/PTHrP receptor was expressed in cultured human keratinocytes and dermal fibroblasts. Northern analyses of poly (A)+ RNA isolated from cultured fibroblasts revealed two PTH/PTHrP receptor transcripts with one major band at 2.5 kb and one minor band at 2.3 kb. These transcripts were consistent with those found in human osteosarcoma cells, which are known to express PTH/PTHrP-R mRNAs. In contrast, after repeated Northern analyses no PTH/PTHrP receptor transcripts were found in poly (A)+ RNA isolated from cultured keratinocytes. Reverse-transcriptase/nested polymerase chain reaction analyses of total RNA isolated from cultured keratinocytes and fibroblasts confirmed the Northern analyses data that the PTH/PTHrP receptor was expressed in cultured fibroblasts but not in cultured keratinocytes. When cultured fibroblasts and keratinocytes were exposed to 10(-7) M PTH (1-34) there was a twofold increase in cAMP levels in the fibroblasts and no demonstrable increase was noted in keratinocytes. These results suggest that skin fibroblasts possess the classical PTH/PTHrP receptor and are target cells for PTH and PTHrP whereas keratinocytes do not have the receptor and are unresponsive to its N-terminal agonist in the stimulation of cAMP formation.

Endocardial mapping of ventricular tachycardia in the intact human ventricle. III. Evidence of multiuse reentry with spontaneous and induced block in portions of reentrant path complex

OBJECTIVES

This study was conducted to characterize the functional nature of the reentrant tract responsible for ventricular tachycardia due to ischemic heart disease.

BACKGROUND

A zone of slow conduction forming the return path is though to form a critical component of the reentrant mechanism in ventricular tachycardia. Despite its importance, detailed knowledge of the return path is rare in clinical studies.

METHODS

Multielectrode arrays were used intraoperatively to obtain unipolar and high gain bipolar recordings of left ventricular endocardium in patients undergoing map-directed surgical ablation of ventricular tachycardia. A total of 224 local electrograms were analyzed for each tachycardia.

RESULTS

Of 10 consecutive patients undergoing intraoperative cardiac mapping, detailed recording of the return tracts of eight ventricular tachycardias were obtained in three patients. The recordings demonstrated that return tracts can be complex and extensive, with multiple paths of entry and exit. Potential and actual alternate paths were observed. Spontaneous and induced block occurred within portions of the complex. Intermittent block in one of two paths of entry resulted in intermittent cycle length changes of the tachycardia without a change in configuration. Block in one exit path resulted in a shift to alternative exit paths, with dramatic changes in ventricular activation and tachycardia configuration. Termination of the tachycardia could result from block close to the entrant or exit portion of the return tract. Different tachycardias were seen to share common portions of a return tract.

CONCLUSIONS

These observations enlarge and extend our knowledge of the functional repertoire of complex reentrant tracts that occur in infarct-related ventricular tachycardia. The use of common portions of a reentrant tract by several tachycardias is confirmed. Utilization of alternate pathways can account for changes in configuration and cycle length. Spontaneous and induced block can occur at points of entry and exit in a reentrant tract and may identify optimal targets for ablation attempts. Further advances will require greater emphasis on diastolic activation mapping.

Identification of soluble protein phosphatases that dephosphorylate voltage-sensitive sodium channels in rat brain

Rat brain sodium channels are phosphorylated at multiple serine residues by cAMP-dependent protein kinase. We have identified soluble rat brain phosphatases that dephosphorylate purified sodium channels. Five separable forms of sodium channel phosphatase activity were observed. Three forms (two, approximately 234 kDa and one, 192 kDa) are identical or related to phosphatase 2A, since they were 85-100% inhibited by 10 nM okadaic acid and contained a 36-kDa polypeptide recognized by a monoclonal antibody directed against the catalytic subunit of phosphatase 2A. Immunoblots performed using antibodies specific for isoforms of the B subunit of phosphatase 2A indicate that the two major peaks of phosphatase 2A-like activity, A1 and B1, are enriched in either B' or B alpha. The remaining two activities (approximately 100 kDa each) probably represent calcineurin. Each was relatively insensitive to okadaic acid, was active only in the presence of CaCl2 and calmodulin, and contained a 19-kDa polypeptide recognized by a monoclonal antibody raised against the B subunit of calcinerurin. Treatment of synaptosomes with okadaic acid to inhibit phosphatase 2A or cyclosporin A to inhibit calcineurin increased apparent phosphorylation of sodium channels at cAMP-dependent phosphorylation sites, as assayed by back phosphorylation. These results indicate that phosphatase 2A and calcineurin dephosphorylate sodium channels in brain, and thus may counteract the effect of cAMP-dependent phosphorylation on sodium channel activity.

Ras oncogene and p53 gene hotspot mutations in colorectal cancers

Ras oncogene and p53 gene mutations are frequently observed in colorectal cancers. The role of co-operation between these two genes in the tumorigenesis of colorectal cancer was evaluated. Point mutations in K-ras oncogene and hotspot codons of p53 gene of colorectal cancers were evaluated by naturally created or amplified created restriction site method. Nine of 42 cases (21.4%) of colorectal cancer showed K-ras oncogene mutations. Six of 42 cases (14.3%) of colorectal cancer showed p53 gene hotspot point mutations. The low frequency of p53 gene mutation in this series may be due to racial difference or different hotspot codons. When six cases with mutated p53 gene were examined, only one (16.7%) showed concurrent K-ras oncogene codon 12 and p53 gene codon 248 mutations. We concluded that the co-operation between ras oncogene and p53 gene hotspot point mutations in the tumorigenesis of colorectal cancer in Chinese was not common. Other factors such as adenomatous polyposis coli gene mutations, oncogene activation or tumour suppression gene inactivation may be involved.

Pharmacokinetics of promazine in patients with hepatic cirrhosis--correlation with a novel galactose single point method

We examined promazine pharmacokinetics in nine patients with hepatic cirrhosis and in six healthy subjects. A specific and sensitive HPLC method was used to measure promazine concentrations in plasma, plasma water (free drug), red blood cells, and urine after oral administration of promazine (2 x 50 mg tablet). There were highly significant reductions in total plasma clearance (p < 0.01), free drug total plasma clearance (p < 0.01), metabolic clearance (p < 0.01), metabolic clearance of free drug (p < 0.01), and fraction bound (p < 0.01) in the cirrhotic patients. The elimination half-life and the area under the plasma concentration-time curve were significantly increased (p < 0.001 and p < 0.05, respectively) in the cirrhotic patients. However, the overall excreted promazine in urine, time to the promazine peak concentration, distribution half-life, renal clearance, apparent volume of distribution, and the promazine concentration ratio between plasma and red blood cells were not different. Thus caution is needed in using promazine for patients with hepatic cirrhosis. A newly developed galactose single point (GSP) method was applied to quantitatively measure the residual liver function in cirrhosis patients and successfully correlated it with promazine elimination half-life (r = 0.770, p < 0.01), total plasma clearance of free drug (r = 0.899, p < 0.005), metabolic clearance of free drug (r = 0.902, p < 0.005), and plasma protein binding (r = 0.822, p < 0.005). GSP may be a convenient index for promazine routine dosage adjustment in patients with liver cirrhosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute transverse myelopathy and cutaneous vasculopathy in primary Sjögren's syndrome

Neurologic complications of primary Sjögren's syndrome (SS) may be under-estimated. Here, we report a patient with primary SS, who developed acute transverse myelopathy (ATM) and skin purpuric lesions simultaneously. In the first episode of myelopathy, the patient's neurologic deficits improved after steroid therapy. However, she died of recurrent myelopathy with systemic complications 4 months later. Review of the English-language literature revealed only 3 cases of primary SS associated with ATM, none of the 3 patients had skin lesions. Anti-Ro(SS-A) antibodies, and ATM in our patient suggests that immune-mediated vasculopathy may play a role in the pathogenesis of acute myelopathy in primary SS.

The antiproliferative and differentiative activities of 1,25-dihydroxyvitamin D3 are potentiated by epidermal growth factor and attenuated by insulin in cultured human keratinocytes

1,25-dihydroxyvitamin D3 (1,25(OH)2D3) is a potent inhibitor of keratinocyte proliferation, as well as a stimulator of epidermal terminal differentiation. In the present studies, we investigated the influence of epidermal growth factor (EGF) and insulin on the antiproliferative and differentiation activities of 1,25(OH)2D3. Our results indicate the following: (1) EGF caused a dramatic potentiation of the 1,25(OH)2 D3-induced inhibition of 3H-thymidine incorporation into keratinocytes in a dose-dependent manner; (2) insulin acted antagonistically on the EGF-dependent potentiation of the 1,25(OH)2D3-induced antiproliferative activity; (3) transforming growth factor-alpha potentiated 1,25(OH)2D3-induced antiproliferative activity similar to EGF; (4) the EGF effect was not dependent upon 1,25(OH)2D3 receptor mRNA up-regulation; and (5) removal of insulin from medium supplemented with growth factors significantly potentiated the 1,25(OH)2D3-induced inhibition on the number of basal cells and the 1,25(OH)2D3-dependent cornified envelope formation. In conclusion, the antiproliferative activity of 1,25(OH)2D3 in cultured normal human keratinocytes is greatly enhanced by EGF or transforming growth factor-alpha and reduced by insulin. Insulin also inhibits 1,25(OH)2D3-induced terminal differentiation of cultured normal human keratinocytes.

Multifocal inflammatory leukoencephalopathy associated with levamisole and 5-fluorouracil: case report

Levamisole and 5-fluorouracil have now become the standard chemotherapeutic regimen for patients with Stage III colon carcinoma. A case of multifocal inflammatory leukoencephalopathy secondary to levamisole alone or combination of levamisole and 5-fluorouracil is reported. Magnetic resonance imaging with gadolinium demonstrated multifocal contrast-enhancing frontal, parietal, occipital, and periventricular white matter lesions. A stereotactic biopsy revealed reactive gliosis and macrophage infiltration, without evidence of metastatic tumor. Despite continuation of 5-fluorouracil, resolution of contrast-enhancing lesions on magnetic resonance imaging without further neurological sequelae occurred when levamisole was stopped. The patient died with evidence of systemic metastasis 6 months later. Autopsy examination of the brain revealed multifocal demyelinating lesions, with no evidence of metastatic tumor. Immunoperoxidase studies of demyelinated lesions demonstrated infiltrating macrophages strongly positive for Class II antigens, interleukin-6, and interleukin-1 alpha. Surrounding astrocytes were positive for granulocyte macrophage colony-stimulating factor. Small numbers of perivascular T cells were present. This patient represents the first autopsy documented case of levamisole associated multifocal inflammatory leukoencephalopathy.

Multifocal inflammatory leukoencephalopathy associated with levamisole and 5-fluorouracil: case report

Levamisole and 5-fluorouracil have now become the standard chemotherapeutic regimen for patients with Stage III colon carcinoma. A case of multifocal inflammatory leukoencephalopathy secondary to levamisole alone or combination of levamisole and 5-fluorouracil is reported. Magnetic resonance imaging with gadolinium demonstrated multifocal contrast-enhancing frontal, parietal, occipital, and periventricular white matter lesions. A stereotactic biopsy revealed reactive gliosis and macrophage infiltration, without evidence of metastatic tumor. Despite continuation of 5-fluorouracil, resolution of contrast-enhancing lesions on magnetic resonance imaging without further neurological sequelae occurred when levamisole was stopped. The patient died with evidence of systemic metastasis 6 months later. Autopsy examination of the brain revealed multifocal demyelinating lesions, with no evidence of metastatic tumor. Immunoperoxidase studies of demyelinated lesions demonstrated infiltrating macrophages strongly positive for Class II antigens, interleukin-6, and interleukin-1 alpha. Surrounding astrocytes were positive for granulocyte macrophage colony-stimulating factor. Small numbers of perivascular T cells were present. This patient represents the first autopsy documented case of levamisole associated multifocal inflammatory leukoencephalopathy.

Expression of 25-hydroxyvitamin D3-24-hydroxylase mRNA in cultured human keratinocytes

It is well documented that 1 alpha,25-dihydroxyvitamin D3 (1 alpha,25[OH]2D3), the most active vitamin D metabolite, inhibits epidermal keratinocyte proliferation and promotes differentiation. 1 alpha,25(OH)2D3 can be produced in keratinocytes from 25-hydroxyvitamin D3 by the enzyme 25-hydroxyvitamin D3-1 alpha-hydroxylase (1-OHase). Hydroxylation of 1 alpha,25(OH)2D3 by 25-hydroxyvitamin D3-24-hydroxylase (24-OHase), the first step in the catabolic pathway of 1 alpha,25(OH)2D3 could significantly reduce the intracellular concentration of 1 alpha,25(OH)2D3. Therefore, the expression of 24-OHase could have a critical regulatory role in 1 alpha,25(OH)2D3-dependent gene expression. As a first step to examine this possibility, the steady state level of 24-OHase mRNA in cultured human keratinocytes (CHK) was investigated. 24-OHase mRNA was not detected in control CHK. 1 alpha,25(OH)2D3 caused a dose- and time-dependent increase in 24-OHase mRNA level. The highest accumulation of 24-OHase mRNA was observed in CHK treated with 0.1-1 microM 1 alpha,25(OH)2D3. The level of 24-OHase mRNA reached a plateau 12-24 hr after 1 alpha,25(OH)2D3 treatment. 1 beta,25-dihydroxyvitamin D3, the stereoisomer of 1 alpha,25(OH)2D3, failed to induce 24-OHase mRNA expression significantly. In addition to 24-OHase mRNA, a 1.0-kb mRNA hybridized strongly with both rat and human 24-OHase cDNA probes. The origin of this 1.0-kb message is unknown at present, however, it was regulated by 1 alpha,25(OH)2D3. These results demonstrate that 1 alpha,25(OH)2D3 up-regulates the expression of 24-OHase mRNA, and this may be an important first step in the initiation of catabolism of 1 alpha,25(OH)2D3 in human keratinocytes.

Brain stem compression secondary to adipose graft prolapse after translabyrinthine craniotomy: case report

Three cases of fat graft prolapse into the cerebellopontine angle with clinical deterioration are presented. These patients had undergone translabyrinthine craniotomy for cerebellopontine angle tumors and had autologous abdominal fat strips placed to obliterate the dural defect and the mastoid cavity. Two patients suffered significant morbidity, and one patient died. Clinical presentation, computed tomographic scan findings, methods of treatment, and avoidance of this complication are discussed.

Cranioplasty with the Medpor porous polyethylene flexblock implant. Technical note

The authors describe the use of a porous polyethylene Flexblock implant for cosmetic cranioplasty. The implant may be used to cover any small- or medium-sized (< 8 cm) cranial defect, offering similar cosmetic results to standard alloplast cranioplasty while decreasing operation time. The porous implant design permits ingrowth of soft tissue and bone to increase implant strength and decrease the risk of infection. The Flexblock alloplast has been utilized in 25 cases with excellent cosmetic results and no implant-related complications.

A parathyroid hormone antagonist stimulates epidermal proliferation and hair growth in mice

The biologic action of parathyroid hormone (PTH)-related peptide (PTHrP) in normal skin was investigated in cultured human keratinocytes and in SKH-1 hairless mice. The results indicate that the PTHrP agonists human PTHrP-(1-34) and PTH(1-34) are potent inhibitors of epidermal cell proliferation. [Nle8,18,Tyr34]bovine PTH-(7-34)-amide, an antagonist of the PTH/PTHrP receptor, blocked the inhibitory effect of PTH-(1-34) in cultured keratinocytes. In the SKH-1 mice, PTH-(7-34) caused a 244% increase of [3H]thymidine incorporation into isolated epidermal DNA and 246% and 180% increases in the number and length of hair shafts, respectively. Thus, PTH and PTHrP may play an important role in the normal physiology of skin, and their agonists and antagonists have potentially wide therapeutic applications in the treatment of hyperproliferative skin disorders and aging skin and could also be effective in stimulating and maintaining hair growth.

New device for biofragmentable anastomotic ring in low anterior resection

PURPOSE

The biofragmentable anastomotic ring (BAR) is now accepted as an alternative anastomotic method to handsewn and stapled anastomosis in colonic surgery. However, for a short rectal stump in a narrow pelvis, it is rather difficult to use the BAR in a low anterior resection.

METHOD

To overcome the difficulty, we designed and used a BAR-adapter to facilitate biofragmentable ring anastomosis following low anterior resection in eight patients with rectal cancers.

RESULTS

There was no case in our series having received conversion to other methods. There was no significant complication associated with this technique.

CONCLUSION

With the BAR-adapter, the applicability of the BAR can be greatly expanded in colorectal anastomosis following low anterior resection.

Characterization of the translocation process of vitamin D3 from the skin into the circulation

The cutaneous synthesis of vitamin D3 and the subsequent translocation of vitamin D3 into the circulation are two key steps in the vitamin D endocrine system. To study the kinetic aspects of cutaneous synthesis and translocation of vitamin D3, both in vitro and in vivo chicken models have been developed. To assess the capacity of chicken skin to generate vitamin D3, the concentrations of 7-dehydrocholesterol (7-DHC) in different skin areas were determined. It was found that the highest concentration of 7-DHC was in the leg skin (3524 +/- 937 ng cm-2), which was about 30 times greater than that in the back (120 +/- 62 ng cm-2). Whole body exposure of chickens to UV-B radiation (0.5 J cm-2) resulted in the production of previtamin D3 (preD3) in the skin of the legs and feet (43 +/- 7 and 54 +/- 17 ng cm-2, respectively), whereas no preD3 was detected in the back skin. In vitro, at 40 C, the forward (k1) and reverse (k2) rate constants of the preD3<-->vitamin D3 reaction in the leg skin were greatly increased compared to those in n-hexane (k1, 0.367 vs. 0.0369 h-1; k2, 0.042 vs. 0.0059 h-1). In vivo, the determined rate constants k1, k2, and k3 for the consecutive reactions preD3<-->vitamin D3-->vitamin D3 were 0.257, 0.034, and 0.114 h-1, respectively. To evaluate the circulating concentration of vitamin D3 in response to UV-B radiation, chicken legs were irradiated. The time course revealed a 4-fold increase in the circulating concentration of vitamin D3, with a peak about 30 h postradiation. No appreciable amount of preD3 could be detected in the circulation in the early hours after UV-B radiation, suggesting the existence of a process responsible for the specific translocation of vitamin D3 from the skin into the circulation.

A possible genetic defect in 25-hydroxylation as a cause of rickets

We examined two siblings who had severe rickets at ages 2 and 7 years, respectively, despite a history of adequate vitamin D intake. The patients' sera had calcium concentrations at the lower limits of normal, low phosphate concentrations, elevated alkaline phosphatase activity, and low levels of 25-hydroxyvitamin D. Treatment with high doses of vitamin D2 resulted in resolution of the biochemical abnormalities and radiographic deformities; pharmacologic doses of vitamin D2 were required to maintain normal concentrations of 25-hydroxyvitamin D in the serum even though vitamin D absorption was normal. These children may have a genetic defect of the 25-hydroxylation step in vitamin D activation.

Protein kinase C inhibitors induce apoptosis in human malignant glioma cell lines

Previous work has demonstrated the importance of the protein kinase C (PKC) system in regulating glioma growth, and has led to clinical trials utilizing PKC inhibitors as adjuncts in the therapy of patients harboring malignant gliomas. This study was performed to explore the possibility that inhibition of PKC in gliomas was triggering an apoptosis signal. Glioma cell lines were treated with PKC inhibitors staurosporine (10 nM), and tamoxifen (10 microM). DNA from cells treated with each of these drugs exhibited a 'ladder' pattern of oligonucleosome-sized fragments characteristic of apoptosis, thus suggesting that in glioma cells, these drugs may be cytocidal in action.

Complex technical methodologies and their applications in the surgery of intracranial meningiomas

As neurosurgery moves into the twenty-first century, improved visualization/localization techniques, neuromonitoring, and advanced instrumentation will become standards of care for all intracranial procedures. This article has focused on current available technologies that can be used to facilitate operations on intracranial meningiomas. Preoperative anatomic localization with MR imaging, CT, MR angiography, and angiography are standard techniques. Preoperative functional assessments with MR imaging, magnetic source imaging, PET, and functional MR imaging are crucial to recognize and preserve eloquent adjacent cortex. Pathologic correlations with preoperative imaging (i.e., MR imaging) may help to predict the histopathology. Perioperative rehearsal of the operation can be performed. Intraoperative anatomic localization is important to minimize the craniotomy, dural opening, and passage through normal neural structures. An impressive array of new technologies are currently available, including real-time ultrasonography, frame-based stereotaxy (CT, MR imaging PET), frameless stereotaxy (acoustic localization, neuronavigators, real-time visualization), robotics, neuroendoscopy, and intraoperative dye administration. Increased understanding of the function and individual variability of the human cortex underscores the importance of intraoperative functional localization by electrocorticography and optical imaging. Continuous intraoperative neuromonitoring of sensory (SSEPs, BAERs, visual evoked potentials) and motor evoked potentials is now standard during many intracranial procedures. Complex adjunctive instrumentation, such as the ultrasonic aspirator and the laser, are part of the contemporary armamentarium for meningioma surgery. As we have stated in a previous article, "Developmental trends imply realization of three major directions of technical neurosurgery: (1) precise preoperative simulation, (2) minimization or avoidance of transcranial operative corridors, [and] (3) increased refinement of technical adjuvants--both physical and molecular." The end point of these technical advances is to improve precision and safety and will enhance the outcome in each surgical procedure so that one day we will be able to operate on patients with intracranial lesions with minimal morbidity.

Headache recurrence in pregnant women with migraine

The goal of this study was to evaluate to what extent pregnancy influences headache recurrence in women with a diagnosis of migraine at, or before, their first prenatal visit. Data from the large, prospective Collaborative Perinatal Project of 55,000 pregnancies were reviewed. Less than 2% of women in the sample of first study pregnancies were considered to have migraine at their initial prenatal visit (n = 508). Of the 484 women with a complete data set, 17% experienced complete cessation of headache throughout pregnancy and another 62% experienced two or fewer headaches in the third trimester. These observations lead to the conclusion that many migraineurs (79% in this sample) experience improvement in headache recurrence during pregnancy. Only 21% experienced no improvement at all. No demographic or obstetrical factor was associated with headache improvement.

Mutation analysis of K-ras oncogenes in gastroenterologic cancers by the amplified created restriction sites method

A rapid, simple, and nonradioactive method for diagnosing point mutations of c-K-ras oncogenes in gastroenterologic cancers is described. This method involved the selective amplification of DNA fragments from cancer tissues of surgical specimens with specific oligonucleotide primers, followed by digestion with restriction enzymes that recognized artificially created or naturally occurring restriction sites. To detect codon 12 mutations, an artificial Msp I site was created by introducing a single nucleotide mismatch into the 5' mutagenesis primer. Using a similar approach, an Hae III site was created to detect codon 13 mutations. Bal I and MBo II sites were used to detect codon 61 mutations. A total of 61 gastroenterologic cancer cases were studied. Of 35 cases of colorectal cancer, 7 showed mutations: 6 at codon 12 and 1 at codon 13. In 1 of 2 cases of cholangiocellular carcinoma, point mutation at codon 12 was found. One case of duodenal cancer showed point mutation at codon 12. No mutations were found in the cases of hepatocellular carcinoma (4), gastric cancer (12), esophageal cancer (3), or pancreatic cancer (2).

"Hot spots" mutation analysis of p53 gene in gastrointestinal cancers by amplification of naturally occurring and artificially created restriction sites

We developed a rapid, simple method to detect "hot spot" point mutations of the p53 gene. A DNA fragment from cancer tissue of a surgical specimen was selectively amplified with specific oligonucleotide primers and then digested with restriction enzymes that recognized artificial or naturally occurring restriction sites. To detect mutations in codons 273 and 245, we created artificial Bst U1 and BgI I sites by introducing a single nucleotide mismatch into the respective mutagenesis primers. We used the naturally occurring restriction sites of Msp I, Hae III, and Hha I to detect mutations in codons 248, 249, and 175, respectively. In 74 cases of gastrointestinal cancer, 5 of 35 colorectal cancers showed mutations; 1 of 15 cases of gastric cancers showed mutation; and 1 of 24 hepatocellular carcinomas showed mutation. This nonradioactive method is an accurate and clinically useful way to detect hot-spot point mutations of the p53 gene in gastrointestinal cancers.

"Hot spots" mutation analysis of p53 gene in gastrointestinal cancers by amplification of naturally occurring and artificially created restriction sites

We developed a rapid, simple method to detect "hot spot" point mutations of the p53 gene. A DNA fragment from cancer tissue of a surgical specimen was selectively amplified with specific oligonucleotide primers and then digested with restriction enzymes that recognized artificial or naturally occurring restriction sites. To detect mutations in codons 273 and 245, we created artificial Bst U1 and BgI I sites by introducing a single nucleotide mismatch into the respective mutagenesis primers. We used the naturally occurring restriction sites of Msp I, Hae III, and Hha I to detect mutations in codons 248, 249, and 175, respectively. In 74 cases of gastrointestinal cancer, 5 of 35 colorectal cancers showed mutations; 1 of 15 cases of gastric cancers showed mutation; and 1 of 24 hepatocellular carcinomas showed mutation. This nonradioactive method is an accurate and clinically useful way to detect hot-spot point mutations of the p53 gene in gastrointestinal cancers.

[Relapsing polychondritis: report of a case and review of the literature]

Relapsing polychondritis (RP) is a rare disease of unknown etiology, characterized by episodic and progressive chondritis, ocular and audiovestibular involvement, and occasional cardiovascular abnormalities. The inflammation typically involves the cartilage of the ears, nose, trachea, larynx, ribs, joints, and Eustachian tubes. The major clinical features include auricular chondritis, arthritis, nasal chondritis, ocular inflammation, chondritis of the respiratory tract, audiovestibular damage, and cardiovascular disorders. RP occurs predominantly in Caucasians and is uncommon in Oriental patients. Two cases of RP have previously been reported in Taiwan. We report one Taiwanese patient who was diagnosed with RP according to the criteria proposed by Damiani and Levine. The patient has bilateral auricular chondritis, episcleritis, and uveitis. Successful treatment was accomplished with systemic corticosteroid and topical corticosteroid eye drops. At an outpatient visit one year and ten months after discharge, there was no evidence of recurrence.

Parathyroid hormone transport effects and hormonal processing in primary cultured rat proximal tubular cells

The development of satisfactory cell culture models for the study of parathyroid hormone (PTH)-induced inhibition of Pi transport has proven difficult. Using subcellular fractionation techniques we investigated the response of primary cultures of rat proximal tubular cells to PTH-(1-34). Specific binding of 125I-bPTH-(1-34) occurred at 2 degrees C. After 5 min of rewarming, trypsin-releasable radioactivity decreased from 90 to 50%, indicating internalization of the ligand. Cell disruption, followed by density centrifugation with 17% Percoll either directly after binding at 2 degrees C or post-rewarming for 20 min, showed a shift of 125I label from the plasma membrane (5'-nucleotidase) to lysosomal fractions (beta-D-glucosaminidase), confirming the sequential occurrence of cell surface binding, internalization and transport to lysosomes of 125I-bPTH-(1-34). Reculture at 37 degrees C revealed steady accumulation of trichloroacetic acid-soluble radioactivity in the medium, indicating degradation of 125I-bPTH-(1-34). Phosphate transport in the absence of sodium was minimal. Incubation of the cells with bPTH-(1-34) resulted in up to 50% inhibition of sodium-dependent phosphate transport. Prior phosphate depletion abrogated the response to PTH.

Kinetic and thermodynamic studies of the conversion of previtamin D3 to vitamin D3 in human skin

The thermoisomerization of previtamin D3 to vitamin D3 is the last step in the synthesis of vitamin D3 in human skin. Kinetic and thermodynamic studies of this reaction in human skin and an organic solvent revealed that not only the equilibrium of the reaction was shifted in favor of vitamin D3 formation in human skin (equilibrium constant K at 37 degrees C = 11.44) compared to hexane (K = 6.15), but also the rate of the reaction was increased by more than 10-fold in human skin (T1/2 at 37 degrees C = 2.5 h) when compared to hexane (T1/2 = 30 30 h). This extraordinarily fast reaction rate was also confirmed in vitro in chicken skin and in vivo in human subjects. The enthalpy change for the reaction determined by the van't Hoff plot was delta H degree = -21.58 kJ mol-1 in human skin and delta H degree = -15.60 kJ mol-1 in hexane. Arrhenius plots showed that the activation energies for both the forward and the reverse reactions were lower in human skin (Ea1 = 71.05 kJ mol-1 and Ea2 = 92.63 kJ mol-1) than in hexane (Ea1 = 84.90 kJ mol-1 and Ea2 = 100.5 kJ mol-1). Activation parameters for the reaction in human skin and in hexane were also reported. Subcellular fractionation of human epidermal tissue revealed that most epidermal 7-dehydrocholesterol and previtamin D3 were in the membrane fraction, while only 20% were in the cytosol. The interaction of previtamin D3 with intracellular lipids and/or proteins in skin may be responsible for the increased vitamin D3 formation rate in the skin.

Does phenobarbital used for febrile seizures cause sleep disturbances?

The effect of phenobarbital on total sleep time, night awakenings, and lengthy awakenings was examined as part of a randomized trial of children with febrile seizures; information about sleep patterns was gathered by parental observation. Children were between ages 8-36 months at enrollment and were examined subsequently for 2 1/2 years. Night awakenings were not more common in children assigned to phenobarbital except for those who were poor sleepers at the beginning of the study. Total sleep time was no different in children assigned to phenobarbital than in those assigned to placebo. It is concluded that sleep problems reported in most young children with febrile seizures treated with phenobarbital did not exceed those reported in children treated with placebo, but a subset of predisposed children did experience an increase in night awakenings.

Differential effects of tumor necrosis factor-alpha on proliferation, cell surface antigen expression, and cytokine interactions in malignant gliomas

Tumor necrosis factor-alpha (TNF-alpha), a cytokine produced by astrocytes in vivo and in vitro, was tested for its effects on two malignant astrocytoma cell lines (A-172, U-87). Both lines were immunoreactive for glial fibrillary acidic protein, vimentin, Class I antigens, and interleukin-6. The lines differed in their expression of Class II and intercellular adhesion molecule-1 (ICAM-1) antigenic determinants: A-172 cells were negative for both Class II and ICAM-1 antigens, while U-87 cells were intensely positive for Class II and weakly positive for ICAM-1. When these astrocytoma cell lines were exposed to TNF-alpha, A-172 growth was stimulated while U-87 growth was inhibited. Furthermore, in U-87 cells, TNF-alpha enhanced both ICAM-1 and interleukin-1 beta (IL-1 beta) expression, and decreased immunoreactivity for transforming growth factor-beta (TGF-beta) protein. In contrast, in the presence of TNF-alpha, A-172 cells remained negative for IL-1 beta and TGF-beta, but showed an increased expression of ICAM-1. These results demonstrate that TNF-alpha can induce changes in growth rate, cytokine production, and surface antigen expression in malignant astrocytomas; however, the nature of these changes is dependent on the specific characteristics of these malignant astrocytomas. The resultant variability in the immunological microenvironment of these tumors may reflect differences in their growth potential.

Magnetic resonance imaging and pathological correlates of meningiomas

We examined the relationships between specific magnetic resonance imaging features and certain gross and microscopic characteristics of meningiomas, including vascularity, gross texture (consistency), and venous sinus involvement. Magnetic resonance imaging scans, surgery reports, and the histopathological findings of tumors were examined retrospectively in 54 patients. Sinus involvement was accurately predicted on T1-weighted images in 9 of 10 cases (P = 0.001) and tumors with cystic changes in 3 of 3 cases. T1-weighted images were not useful for predicting vascularity unless actual flow voids could be visualized (five of six cases). There was no correlation between T1 signal intensity, tumor consistency, or histological findings. In tumors without detectable vascularity on T1-weighted images, hyperintensity relative to gray matter on T2-weighted images was correlated with increased vascularity (P = 0.004). Tumors with soft consistency (P = 0.007), cellular atypia, invasion, angioblastic, or melanocytic components were also hyperintense, compared with gray matter on T2-weighted images (P = 0.0266). Aggressive meningiomas were found to be more vascular (P = 0.045). No correlation was found between the degree of surrounding edema or contrast enhancement with histopathological findings, vascularity, or consistency.

[Clinical evaluation of gingival tissue restored with stainless steel crown]

The use of stainless steel crown for the restoration of primary molars is widely accepted in pediatric dentistry. There has been a concern regarding their effect on the health of the gingival tissue. It is a possibility that the preformed crown may be a contributing cause of gingivitis. This study evaluated one hundred and thirty-seven crowns in forty-five patients who had received pedodontic treatment at Chang Gung Memorial Hospital. The results indicated that the majority of stainless steel crowns had one or more defects, with crown crimping being the most common error. According to what the paired t-test showed, non-ideal crowns indicated that the gingival index was significantly higher than the entire mouth and control teeth. However the supragingival plaque accumulation of these teeth was significant lower than the entire mouth and control teeth. There was only a moderate positive correlation between supragingival plaque and gingivitis. The operator is necessary to adapt the stainless steel crown margin as closely as possible to the tooth and to avoid the mechanical defect of a crown. It minimizes the irritation of gingival tissue and diminishes the bacterial adherence of subgingival plaque, therefore preserving the health of gingival tissue.

Development of object vision in infants with permanent cortical visual impairment

We examined 30 infants in whom cortical visual impairment was diagnosed during their first year of life to ascertain prognostic factors for the development of object vision, defined as the ability to recognize faces or hand-held toys. All patients were followed up for a minimum of 12 months. The most common causes of cortical visual impairment in the 30 infants were hydrocephalus in nine infants (30.0%), birth asphyxia or neonatal hypoxia in eight infants (26.7%), intracranial hemorrhage with or without hydrocephalus in seven infants (23.3%), and meningitis in five infants (16.7%). Lack of development of object vision was associated only with hypoxia (P = .013). Findings on ophthalmic examination, an abnormality in the visual pathway on computed tomographic or magnetic resonance scan, and seizures, hydrocephalus, intracranial hemorrhage, meningitis, cerebral palsy, developmental delay, prematurity, microcephaly, and hearing deficit, did not appear to be risk factors for the lack of development of object vision.

Mechanisms of spontaneous shift of surface electrocardiographic configuration during ventricular tachycardia

OBJECTIVES

The aim of this study was to examine, with multichannel direct cardiac mapping techniques, the mechanisms of spontaneous shift of the QRS configuration in the surface electrocardiogram during episodes of ventricular tachycardia.

BACKGROUND

Ventricular tachycardias demonstrating a spontaneous shift in their surface electrocardiographic (ECG) features are occasionally encountered. It is not known whether such changes in configuration are primarily due to a significant change in the tachycardia site of origin or represent alterations in patterns of endocardial and epicardial activation. Knowledge of these features would be helpful, particularly when ablative therapy is considered for the arrhythmias.

METHODS

During map-directed cardiac surgery, episodes of ventricular tachycardia were mapped from 224 epicardial and endocardial sites. Episodes of pleomorphic tachycardia were identified and isochronal maps of endocardial and epicardial activation were constructed from representative beats before and after the change in configuration.

RESULTS

From 52 consecutive patients who underwent detailed intraoperative mapping, 9 patients with pleomorphic ventricular tachycardia were identified in whom 14 episodes of spontaneous shift occurred. An analysis of the epicardial activation patterns revealed that the sites of earliest epicardial breakthrough showed significant alteration at the time of QRS shift in all occurrences. In 10 of these shift episodes, however, the sites of tachycardia origin, located on the endocardial surface, remained closely adjacent (< 2 cm apart). Although these sites of origin remained relatively constant, significant alterations in the patterns of endocardial activation were seen in most episodes. These included changes in the direction of propagation of the wave front of activation and shifts between monoregional and figure eight patterns of activation.

CONCLUSIONS

In most episodes of pleomorphic ventricular tachycardia, the arrhythmia site of origin remains relatively constant. However, patterns of epicardial activation do undergo significant change and appear to be the major determinant of the QRS configuration on the surface ECG.

Endocardial mapping of ventricular tachycardia in the intact human heart. II. Evidence for multiuse reentry in a functional sheet of surviving myocardium

OBJECTIVE

The purpose of this study was to obtain improved detection and characterization of reentrant circuits in the infarcted human ventricle.

BACKGROUND

The return path of reentrant ventricular arrhythmias usually is not manifested in clinical mapping studies but is thought to be formed by isolated bundles of surviving myocytes whose presence is difficult to detect by standard recording techniques.

METHODS

We obtained simultaneous unipolar and high gain bipolar recordings using a left ventricular endocardial balloon array in 10 patients with chronic ischemic heart disease undergoing intraoperative mapping of ventricular tachycardia.

RESULTS

Three patients demonstrated seven separate ventricular tachycardias that utilized a return tract that was manifested on up to 20% of all left ventricular electrode sites. The recordings suggested an extensive sheet of surviving myocardial fibers with multiple entry and exit points allowing for different reentrant paths at different times all in the same heart. In one patient, five different ventricular tachycardias could be induced, four of which utilized such a sheet. Two of these tachycardias had the same exit point (site of origin) but two different entry points with a long and short return path resulting in long and short tachycardia cycle lengths. The same sheet sustained another tachycardia with one entry and two exit points resulting in two separate "sites of origin" on the endocardium. Such sheets also were seen to insert into the left bundle system. In one patient portions of the sheet could be detected epicardially.

CONCLUSION

The existence of such a structure of surviving myocardium with functional pleomorphism may account for unexplained changes in tachycardia cycle length, epicardial entrainment and spontaneous morphologic changes during ventricular tachycardia.

[The comparison of microleakage among three different dentin bonding agents in class V cavities]

The use of the etching technique and an enamel bonding agent may effectively reduce microleakage of the cavity wall. However, the reduction of marginal leakage relating to class V cavities, is still unsatisfactory according to the dental literature. Due to the structural difference between the dentin and the enamel, though many new dentin bonding agents have been developed lately, none of them work perfectly. In this experiment, the "silver staining technique" was used to investigate the degree of microleakage in class V resin restorations which were bonded with 3 different dentin bonding agents (Scotchbond, Scotchbond 2 and Denthesive). The sample consists of 21 caries free human molars which were divided into 3 groups: 1) Scotchbond v. s. Scotchbond 2, 2) Scotchbond v. s. Denthesive, 3) Scotchbond 2 v. s. Denthesive. Both buccal and lingual surfaces were prepared for class V cavities. The cavities were then filled with composite resin Silux, and immersed in 50% silver nitrate solution for 2 hours, and followed by washing with distilled water. After that these teeth were immersed in photodeveloping solution under the fluorescent light for 3 hours. On finishing, they were washed again, sectioned vertically into mesial and distal halves with a Isomet sectioner and put under a microscope and evaluated for the degree of microleakage with Dr. Going's method. On statistical analysis, the results of this study showed that the degree of microleakage was not significantly different among the 3 dentin bonding agents in class V resin restorations, either on the gingival wall or the occlusal wall.

Ventricular tachycardia after surgical repair of tetralogy of Fallot: results of intraoperative mapping studies

OBJECTIVES

Four patients with previous repair of tetralogy of Fallot and ventricular tachycardia underwent map-guided surgery to ablate the arrhythmias.

BACKGROUND

Although patients with repaired tetralogy of Fallot are at increased risk of sudden death due to ventricular tachycardia, little is known of the origin and mechanism of this arrhythmia.

METHODS

A customized right ventricular balloon with 112 electrodes was used to record endocardial activation and, where possible, simultaneous epicardial recordings were obtained with a sock electrode array. Three patients had an aneurysm of the right ventricular outflow tract and one had a septal aneurysm. All had moderate to severe pulmonary valve insufficiency. Preoperative electrophysiologic study demonstrated inducible rapid (cycle length 180 to 300 ms) hemodynamically unstable monoform ventricular tachycardias.

RESULTS

Intraoperatively, five different tachycardias (two in one patient) were induced and mapped. The sites of earliest activation were located in the subendocardium of the right ventricular outflow tract in all, but they varied widely among the septum, free wall and parietal band and could not be identified by visible scar. All were due to a macroreentrant circuit initiated by a critical delay in activation beyond a functional arc of block. Two patients treated by cryoablation while the heart was beating and perfused at normal temperature had inducible ventricular tachycardia postoperatively. In the two subsequent patients, the application of cryoablation under anoxic cardiac arrest resulted in noninducibility of arrhythmia.

CONCLUSIONS

Ventricular tachycardia in tetralogy of Fallot in these four patients was caused by macroreentry in the right ventricular outflow tract. Surgical success depends on detailed mapping and cryoablation under anoxic cardiac arrest. In patients at risk of sudden death, map-directed surgery may offer distinct advantages over either implantable devices or drug therapy.

Molecular characterization of glucose-6-phosphate dehydrogenase (G6PD) deficiency by natural and amplification created restriction sites: five mutations account for most G6PD deficiency cases in Taiwan

We have developed a rapid and simple method to diagnose the molecular defects of glucose-6-phosphate dehydrogenase (G6PD) deficiency in Chinese in Taiwan. This method involves the selective amplification of a DNA fragment from human G6PD gene with specific oligonucleotide primers followed by digestion with restriction enzymes that recognize artificially created or naturally occurring restriction sites. Ninety-four Chinese males with G6PD deficiency were studied. The results show that 50% (47 of 94) were G to T mutation at nucleotide (nt) 1376, 21.3% (20 of 94) were G to A mutation at nt 1388, 7.4% (7 of 94) were A to G mutation at nt 493, 7.4% (7 of 94) were A to G mutation at nt 95, 4.2% (4 of 94) were C to T mutation at nt 1024, 1.1% (1 of 94) was G to T mutation at nt 392, and 1.1% (1 of 94) was G to A mutation at nt 487. These results show that the former five mutations account for more than 90% of G6PD deficiency cases in Taiwan. Aside from showing that G to T change at nt 1376 is the most common mutation, our research indicates that nt 493 mutation is a frequent mutation among Chinese in Taiwan. We compared G6PD activity among different mutations, without discovering significant differences between them.

Hypervitaminosis D associated with drinking milk

BACKGROUND

Vitamin D has been added to milk in the United States since the 1930s to prevent rickets. We report the unusual occurrence of eight cases of vitamin D intoxication that appear to have been caused by excessive vitamin D fortification of dairy milk.

METHODS

Medical records were reviewed and a dietary questionnaire was sent to eight patients who had unexplained hypervitaminosis D. Vitamin D analyses with high-performance liquid chromatography were performed on samples of the patients' serum, the dairy milk they drank, and the vitamin D concentrate added to the milk.

RESULTS

All eight patients drank milk produced by a local dairy in amounts ranging from 1/2 to 3 cups (118 to 710 ml) daily. All had elevated serum 25-hydroxyvitamin D concentrations (mean [+/- SD], 731 +/- 434 nmol per liter [293 +/- 174 ng per milliliter]). Six of the eight patients had elevated serum vitamin D3 concentrations. Of the eight patients, seven had hypercalcemia and one had hypercalciuria but normocalcemia (mean serum calcium, 3.14 +/- 0.51 mmol per liter [12.6 +/- 2.1 mg per deciliter]). Analysis of the dairy's vitamin D-fortified milk revealed concentrations of vitamin D3 (cholecalciferol) that ranged from undetectable to as high as 232,565 IU per quart (245,840 IU per liter). An analysis of the concentrate that was used to fortify the milk, labeled as containing vitamin D2 (ergocalciferol), revealed that it contained vitamin D3.

CONCLUSIONS

Hypervitaminosis D may result from drinking milk that is incorrectly and excessively fortified with vitamin D. Milk that is fortified with vitamin D must be carefully monitored.

The vitamin D content of fortified milk and infant formula

BACKGROUND

The fortification of milk and infant formula with vitamin D has had an important role in eliminating rickets in children and osteomalacia in adults. A recent outbreak of vitamin D intoxication caused by drinking milk fortified with excess vitamin D has led to questions about the level of vitamin D in milk from other producers.

METHODS

We used high-performance liquid chromatography to measure vitamin D in samples of 13 brands of milk with various fat contents and 5 brands of infant formula purchased at random from local supermarkets in five Eastern states.

RESULTS

Only 12 (29 percent) of the 42 samples of the 13 brands of milk and none of the 10 samples of the 5 brands of infant formula contained 80 to 120 percent of the amount of vitamin D stated on the label. Twenty-six of the 42 milk samples (62 percent) contained less than 80 percent of the amount claimed on the label. No vitamin D was detected in 3 of the 14 samples of skim milk tested (lower limit of assay, 4.7 IU per quart [5.0 IU per liter]). One milk sample labeled as containing vitamin D2 (ergocalciferol) contained vitamin D3 (cholecalciferol). Seven of the 10 samples of infant formula contained more than 200 percent of the amount stated on the label; the sample with the highest concentration contained 419 percent of the stated amount. None of the samples of infant formula contained less than the amount stated.

CONCLUSIONS

Milk and infant-formula preparations rarely contain the amount of vitamin D stated on the label and may be either underfortified or overfortified. Since both underfortification and overfortification are hazardous, better monitoring of the fortification process is needed.

Huge plexiform neurofibroma of the head and liver--case report

Neurofibromatosis (NF) is a hereditary autosomal dominant disorder. Von Recklinghausen first described NF in 1882, which is now classified as Neurofibromatosis 1 (NF-1). NF-1 is the most commonly encountered NF which affects 1 in 4000 persons. Clinical manifestations of NF-1 include: generalized cutaneous neurofibroma, pigmented skin patches (cafe-au-lait spots), pigmented iris hamartoma (Lisch nodules), skeletal abnormally, CNS tumors, etc. The subject of this case study is a young adult male with a huge plexiform neurofibroma involving both the liver and head regions. The head tumor measured 10 x 8 x 3.5 cm3 in size, weighted approximately 180g with overlying hyperpigmented skin and an underlying congenital skull defect. A CT scan and MRI of the head and neck revealed a well defined lobulated tumor and deformed external ear. A abdominal sonogram, CT scan and MRI showed a huge plexiform neurofibroma with liver invasion. Lisch nodules and multiple cafe-au-lait spots were also found. Surgical removal of the head tumor along with an external ear reconstruction was performed. Satisfactory cosmetic results and improved hearing were achieved.

Analysis of ras gene mutations in gastrointestinal cancers

Point mutations of c-Ki-ras genes were analyzed in 33 samples of human gastrointestinal malignancy. DNA extracted from the frozen tissue was amplified by polymerase chain reaction (PCR) and analyzed by direct sequencing and slot-blot hybridization at codons 12, 13 and 61 of c-Ki-ras. In 7 cases out of 19 colorectal cancers, point mutations were found: 3 cases at codon 12, 1 at codon 13, 2 at codon 61 of c-Ki-ras and one case had double mutations at codon 12 and codon 13. In 11 cases of gastric cancer, 4 showed point mutations: 1 at codon 12 and 3 at codon 13 of c-Ki-ras. In 3 pancreatic carcinomas, 2 had point mutations: one at codon 12 and the other at codon 13 of c-Ki-ras. The results indicate that c-Ki-ras gene point mutations are involved in the tumorigenesis of the human gastrointestinal system.

Monostotic fibrous dysplasia of the clivus. Case report

A case report of monostotic fibrous dysplasia of the clivus in a postadolescent woman is described. Although fibrous dysplasia of craniofacial structures is well documented, involvement of the clivus has not been reported. Diagnosis by clinical, radiographic, and histopathological features is detailed. Implications for the role of surgery and management are discussed.

Serum zinc and copper during long-term total parenteral nutrition

Changes in serum zinc and copper levels were studied in 17 patients who received 18 courses of total parenteral nutrition for 28 to 89 days. Mean serum zinc levels decreased significantly after 4 weeks of therapy in the group without zinc supplementation when compared with pretreatment levels (p less than 0.05) and in a second group who received about 1.5 mg of zinc per day (p less than 0.05). Serum copper levels fell consistently and significantly in patients of both groups. However, no obvious clinical signs or symptoms of zinc or copper deficiencies were observed. Blood transfusions were not able to significantly change the serum levels of zinc or copper. Although serum alkaline phosphatase has been suggested as a functional indicator of zinc deficiency, the concomitant hepatic or skeletal dysfunction of the patients made its interpretation difficult. These findings indicate that a decrease in serum zinc and copper is common during TPN using solutions unsupplemented with these trace elements. Supplementation of TPN solutions with zinc, copper, and other trace elements is recommended.

Two bacteriophage T4 base plate genes (25 and 26) and the DNA repair gene uvsY belong to spatially and temporally overlapping transcription units

The bacteriophage T4 DNA recombination-repair gene uvsY located at or near an origin of DNA replication and adjacent to the late base plate genes 25 and 26. Our present results reveal a complex transcription pattern in the region encompassing these genes. Most significantly, uvsY and two ORFs, downstream of it, all of which are transcribed from a middle promoter before the onset of DNA replication, are also part of a larger late transcription unit which includes the base plate genes 25 and 26. The late genes 25 and 26 are transcribed not only late, but also early from one or several early promoters further upstream. Translation, however, is inhibited by secondary structures which sequester the ribosome binding site in the early transcript. We discuss possible advantages of these transcriptional patterns for T4 DNA recombination, replication, and repair. The predicted and in vivo-expressed 23.9-kDa product of gene 26 is smaller than the reported size of gene 26 protein isolated from base plates, suggesting that nascent gp26 might be processed to a larger protein during assembly.

The construction of endocardial balloon arrays for cardiac mapping

The advent of multichannel recording systems has enabled clinical mapping to be performed on a beat-by-beat basis using multi-electrode arrays. Surgical ablation of ventricular arrhythmias generally requires endocardial mapping. Clinical usage has indicated that an inflatable balloon array is the most practical design and can obviate the need for ventriculotomy by a transatrial introduction in the deflated state. Successful experience with the left ventricular balloon led to the development of a right ventricular balloon array suitably configured to extend into the outflow tract. Custom moulds are used to create an appropriate balloon from liquid latex. Nylon cloth is cut from a cardboard pattern to fashion a stretchable sock to envelope the balloon. Electrodes are formed by stitching 2-mm silver beads to the balloon sock in a preconfigured pattern. Teflon-coated 31 G multi-strand stainless-steel wires 130 mm in length connect the electrode beads by solder to the multipin connectors for easy hookup to the amplifier inputs. Tygon tubing 0.53 cm in diameter fitted to the balloon allows inflation and pressure monitoring. This basic design has been successfully implemented for the last 6 years.

Asthma and eczema in children born to women with migraine

Migraine and asthma have been reported to occur in the same person more commonly than would be expected if they are independent. The large Collaborative Perinatal Project provided an opportunity to see if children born to women with migraine or with the group of disorders characterized by asthma and/or allergies were more likely to manifest asthma or eczema in the first 7 years of life. Among children whose mothers had neither migraine nor asthma/allergies, 3.2% had asthma. Of children whose mothers had migraine, but not asthma/allergies, more than 6% had asthma. The risk of asthma among children born to women who had both migraine and asthma/allergies was greater than the risk associated with each maternal disease. The risk of eczema in children was not appreciably influenced by the mother's propensity to migraine or asthma/allergies. The results of this first study of migraine in one generation and asthma in the next lead to the conclusion that the two disorders are probably related.

Biosynthesis and processing of renal mitochondrial glutaminase in cultured proximal tubular epithelial cells and in isolated mitochondria

Primary cultures of rat renal proximal tubular epithelial cells were used to characterize the biosynthesis and processing of the mitochondrial glutaminase. When the cells were labeled with [35S]methionine in the presence of 20 microM carbonylcyanide m-chlorophenylhydrazone, only a 72-kDa peptide, which co-migrates with the primary translation product of the glutaminase mRNA, was immunoprecipitated. At lower concentrations of carbonylcyanide m-chlorophenylhydrazone, the 68- and 65-kDa peptides that are characteristic of the mature glutaminase and a 71-kDa peptide were synthesized. Pulse-chase experiments suggest that the 72-kDa cytosolic precursor could be quantitatively chased to generate the mature mitochondrial species. The observed kinetics indicate that the 71-kDa species is an intermediate in the import pathway. In addition, the 65-kDa glutaminase peptide was synthesized more rapidly than the 68-kDa peptide, and the two peptides were produced in a final ratio of 3:1, respectively. These results suggest that one subunit of the tetrameric glutaminase may be subject to covalent modification. In vitro processing was also characterized by incubating isolated rat liver mitochondria with the glutaminase precursor that was produced by in vitro translation of acidotic rat renal poly(A+) RNA. This system produced an identical sequence of processing reactions. The in vitro formation of the 71-kDa intermediate required a transmembrane potential. Both the intermediate and the mature forms of the glutaminase were recovered in the mitochondria and were resistant to trypsin digestion. Thus, the glutaminase precursor is rapidly translocated across the inner mitochondrial membrane and initially processed to yield an intermediate. The intermediate is subsequently processed to yield the two peptides that constitute the mature enzyme.