Characterization of the high and low affinity components of the renal Ca2(+)-Mg2+ ATPase

The purpose of this study was to characterize the interrelationship between free calcium (Ca2+) and magnesium (Mg2+) in the Ca2+ ATPase enzyme cycle of kidney membranes. Experiments were performed with basolateral membranes from rat renal cortex and microdissected proximal and distal tubules from mice. Results were similar in the three types of preparations. We first investigated the effect of ATP concentration on Ca2(+)- and Mg2(+)-dependent ATP hydrolysis. With 0.2 microM Ca2+, the enzyme activity, as a function of ATP concentration, showed two saturable components: a high affinity component with a Km of 33 microM ATP and a low affinity component with a Km of 0.63 mM ATP. These components may represent either two distinct sites of ATP binding or two forms of the same site. For the sake of simplicity, it was assumed that the two components correspond to a high affinity and a low affinity substrate site. At the high affinity site (ATP = 50 microM), the Ca2+ dependence of ATP hydrolysis followed a single Michaelis-Menten kinetics with Km for Ca2+ of 0.08 microM. The addition of 1 mM Mg2+ resulted in a relatively constant increase in ATP hydrolysis at all Ca2+ concentrations, indicating that the effects of the two cations were additive. With high ATP concentration (ATP = 3 mM), Ca2+ also induced an ATP hydrolysis according to a saturable process, with a Km for Ca2+ of 0.2 microM. In contrast with what occurred with low concentrations of ATP, addition of millimolar Mg2+ completely curtailed the sensitivity of the enzyme to Ca2+.(ABSTRACT TRUNCATED AT 250 WORDS)

Twelve years' experience of computer-aided diagnosis in a district general hospital

This paper describes experience in a modern district general hospital with a small desktop system for computer-aided diagnosis of acute abdominal pain, over a 12-year period involving 5512 cases. When compared with a baseline year (1973) in which unaided performance was monitored, during an initial study period (1974-76) the diagnostic accuracy of junior staff rose by between 10 and 15%. This higher performance level was then maintained for a decade (1976-86) despite changes in staff. The perforation rate among appendicitis cases fell from 27% to 12.5%, accompanied by a smaller fall in negative laparotomy rates. The saving in surgical bednights devoted to acute abdominal pain was approximately 15%, and the notional cost of resources saved during the first 6 years of operation was 120,000 pounds. Other hospitals have shown--in the short term--benefits similar to those obtained at Airedale District General Hospital. The long-term benefits of the system at Airedale reinforce the conclusions of the earlier short-term trials that a comparable system should probably be offered to all DGHs in the UK, not as an exercise in 'artificial intelligence' but as an effective continuing stimulus to good clinical practice.

Hepatocellular carcinoma in Hong Kong: clinical study on 340 cases

Three hundred and forty cases of hepatocellular carcinoma in Hong Kong were studied for their clinical features, and various factors were analysed for their prognostic values. The clinical presentation was often vague and rather non-specific and a majority of patients were presented late and often unresectable. The overall median survival was 8 weeks. The Karnofsky performance scale and bilirubin level were the most important prognostic factors. The treated group survived longer than the untreated group.

Sonographic diagnosis of portal vein invasion in patients with hepatocellular carcinoma: comparison with arterial portography

The results of sonographic assessment of the main portal vein were compared with arterial portography in 65 patients with documented hepatocellular carcinoma. When compared with fully-diagnostic angiograms, obtained in 54 patients, sensitivity of ultrasound was 64% with a specificity of 98%. We conclude that ultrasound is a valuable first-line method of detecting portal vein invasion in the preoperative assessment of patients with hepatocellular carcinoma.

Adhesive strength of single muscle cells to basement membrane at myotendinous junctions

Whole muscles loaded to failure frequently fail at or near myotendinous junctions. The present investigation was directed toward determining the breaking stress and failure site of intact and injured myotendinous junction preparations consisting of muscle cells dissected free from surrounding parallel structures but still attached to tendon collagen fibers. These tests show that the breaking stress for intact myotendinous units is 2.7 x 10(5) N/m2, expressed relative to cell cross-sectional area. Failure occurs immediately external to the junction membrane between the cell membrane and lamina densa of the basement membrane. Site and stress at failure are independent of strain and strain rate over a biologically relevant range. Breaking stress in the plane of the membrane, corrected for membrane folding, is 1.2 X 10(4) N/m2. This value is not significantly greater than stress at maximum isometric tension for these cells at these sarcomere lengths. After compression injury, cells fail within the compression site at significantly lower stress (1.9 X 10(5) N/m2). These findings suggest that, in muscle strain injuries that occur under conditions simulated here, failure occurs at myotendinous junctions unless the muscle has suffered previous compression injury leading to failure within the muscle.

Respiratory control: its contribution to the treatment of panic attacks. A controlled study

Patients who experienced panic attacks, with or without avoidance, were treated for two weeks with either training in controlled breathing or a placebo treatment. Subsequently, both groups received a limited period of conventional anxiety treatments, most commonly in vivo exposure. Patients were subdivided into 'hyperventilators' and 'non-hyperventilators' on the basis of the conventional provocation test. Observer ratings of anxiety showed a greater improvement for the group that received breathing training, but there was no evidence that 'hyperventilators' benefited more from respiratory training than 'non-hyperventilators'. Self-report measures of anxiety, avoidance, and depression/dysphoria showed no difference between treatments. These findings suggest that training in controlled breathing is not of specific benefit for those identified as 'hyperventilators' by the provocation test, but that it may have a non-specific effect in the treatment of patients with panic attacks.

Aspiration cytology in the management of breast lesions

In a group of patients with breast lumps, diagnosis made by pre-operative aspiration cytology was compared with that obtained by histological section of excised specimens. Results showed that aspiration cytology correctly diagnosed 89% of malignant lesions and 92.6% of benign lesions based upon histological diagnosis. Cytological diagnosis of benign disease had a false negative rate of 6% while cytological diagnosis of malignant disease had a 2.7% false positive rate. Only 3.5% of cytologies returned an inadequate diagnosis. This study shows that aspiration cytology should be useful in allowing a better psychological preparation of patients before surgery as well as better utilization of operation theatre facilities.

Comparative use of amino acids by three auxotypes of Neisseria gonorrhoeae

Auxotypes of Neisseria gonorrhoeae are usually distinguishable by their particular requirements for growth; these requirements often include amino acids. It is possible that strains needing particular substrates to grow can be distinguished not merely by their growth requirements but also by their metabolism of these particular substrates. In this work amino acid utilization and oxidation studies were performed enabling prototype, pro- and thia-strains to be distinguished. The metabolism study also underlined the importance of proline as an energy source and pointed to the probability of distinct relationships with the metabolism of the key amino acids, glutamic and aspartic acids, for the three auxotypes. It is proposed that the specific amino acid required by the naturally occurring auxotype serves as an energy source at the site of infection and has important implications with respect to particular auxotypes at various sites.

Endometrial carcinoma in a young woman

We present an unusual case of endometrial carcinoma which developed in a 22-year-old woman shortly after pregnancy.

Treatment of residual and recurrent cervical metastasis from nasopharyngeal carcinoma

Eleven patients with cervical metastases from nasopharyngeal carcinoma were studied. Even after adequate radiotherapy treatment, viable tumour cells were detected in all patients. Nine patients underwent radical neck dissection and the histological study of the specimens confirmed the operative findings. The extent of the disease was far greater than the clinical assessment suggesting that simple lymphadenectomy is an inadequate form of treatment.

High affinity Ca2+ -Mg2+ ATPase in the distal tubule of the mouse kidney

The purpose of this study was to investigate whether Ca2+ -Mg2+ ATPase in the distal tubule (where calcium transport is active, against a gradient, and hormone dependent) presents some characteristics different from those observed in the proximal tubule, and whether these characteristics are likely to shed light on the respective roles of this enzyme at the two sites of the nephron. The Ca2+ - and Mg2+-dependent ATP hydrolysis was measured in microdissected segments of the distal nephron, the kinetic parameters were determined, and the influence of magnesium upon the sensitivity to calcium was examined. Results were compared with those obtained in the proximal tubule, and in purified membranes as reported by others. In the distal tubule, low concentrations of Mg2+ (less than 10(-7) M) did not influence ATP hydrolysis. At concentrations above 10(-7) M, Mg2+ increased ATP hydrolysis according to Michaelis kinetics (apparent Km = 11.3 +/- 2.4 microM, Vmax = 219 +/- 26 pmol.mm-1.20 min-1). The addition of 1 microM Ca2+ decreased the apparent Km for Mg2+ and the Vmax for Mg2+. Similar results were obtained in the proximal tubule. At low Mg2+ concentrations, Ca2+ also stimulated ATP hydrolysis according to Michaelis kinetics with an apparent Km value for Ca2+ of 0.18 +/- 0.06 and 0.10 +/- 0.03 microM Ca2+ (ns) and a Vmax of 101 +/- 12 and 89 +/- 9 pmol.mm-1.20 min-1 (ns) in the distal and proximal tubules, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

The human and murine influenza-specific B cell repertoires share a common idiotope

We have dissected the human influenza-specific B cell repertoire by performing Epstein-Barr virus (EBV) limiting dilution analysis of lymphocytes obtained from donors before and after immunization with a commercially available influenza vaccine. In addition to an analysis of precursor frequency and light chain diversity, we studied sera and culture supernatants containing human anti-influenza antibodies with a panel of murine monoclonal antibodies specific for idiotopes identified on murine anti-PR8 and anti-X-31 antibodies. An idiotypic specificity present on the X-31-specific murine monoclonal PY206 has previously been shown to be shared by murine antibodies specific for PR8, X-31, and other influenza viruses. We observed little correlation among the following parameters: anti-viral titer, serum idiotope content, precursor frequency and immune status. More interestingly, there was a striking predominance of human influenza-specific antibodies that utilized lambda light chains. In addition, 12 of 26 human anti-influenza monoclonals strongly inhibited the binding of one of the murine anti-idiotopes to the labeled murine antibody, PY206. This is the same idiotope that is shared among murine antiinfluenza antibodies and all six individuals studied contained clones reactive with this anti-idiotope. Seven of these 12 idiotope-positive human antibodies gave partial cross-reactivity in a second anti-idiotypic system. These observations imply that a significant level of homology exists between the binding sites of human and murine influenza-specific antibodies and suggest that idiotypic manipulation of the human immune response to influenza virus may have important therapeutic implications.

The human and murine influenza-specific B cell repertoires share a common idiotope

We have dissected the human influenza-specific B cell repertoire by performing Epstein-Barr virus (EBV) limiting dilution analysis of lymphocytes obtained from donors before and after immunization with a commercially available influenza vaccine. In addition to an analysis of precursor frequency and light chain diversity, we studied sera and culture supernatants containing human anti-influenza antibodies with a panel of murine monoclonal antibodies specific for idiotopes identified on murine anti-PR8 and anti-X-31 antibodies. An idiotypic specificity present on the X-31-specific murine monoclonal PY206 has previously been shown to be shared by murine antibodies specific for PR8, X-31, and other influenza viruses. We observed little correlation among the following parameters: anti-viral titer, serum idiotope content, precursor frequency and immune status. More interestingly, there was a striking predominance of human influenza-specific antibodies that utilized lambda light chains. In addition, 12 of 26 human anti-influenza monoclonals strongly inhibited the binding of one of the murine anti-idiotopes to the labeled murine antibody, PY206. This is the same idiotope that is shared among murine antiinfluenza antibodies and all six individuals studied contained clones reactive with this anti-idiotope. Seven of these 12 idiotope-positive human antibodies gave partial cross-reactivity in a second anti-idiotypic system. These observations imply that a significant level of homology exists between the binding sites of human and murine influenza-specific antibodies and suggest that idiotypic manipulation of the human immune response to influenza virus may have important therapeutic implications.

Differences in diazepam pharmacokinetics in Chinese and white Caucasians--relation to body lipid stores

We have compared diazepam pharmacokinetics in 16 Chinese and 18 white Caucasian healthy male volunteers, resident in Hong Kong and have correlated them with physical attributes. Serum concentrations of diazepam and desmethyldiazepam were measured in venous blood by an enzyme-linked immunoassay (0-3 h samples) and HPLC (3-72 h samples). Pharmacokinetic parameters were derived assuming a two compartment model, distribution phase less than 6 h, and 100% oral systemic availability. Compared with the Chinese the white Caucasians were older, heavier, taller, and fatter, as judged by skin fold thickness (SFT) and total body weight to 'Ideal' body weight (TBW/IBW) ratio; respective mean differences being 16%, 27%, 4%, 26%, and 15% (p less than 0.05). Mean diazepam apparent volume of distribution (V) and V/IBW were larger in the white Caucasians (52% & 39% respectively, p = 0.002). SFT and TBW/IBW ratio yielded the best correlations with V, V/TBW and V/IBW (0.50-0.75, p less than 0.05). Obesity indices contributed most to the overall regressions (R2 up to 0.52), and for V there was a further small effect (2%, partial F test) due to ethnic group, possibly reflecting stature. Mean peak diazepam concentration (Cmax) was similar in both ethnic groups. Time to Cmax (tmax) was more often prolonged in the Chinese (chi 2 test, p = 0.01). Body fat and stature may thus account for these inter-ethnic differences in the apparent volume of distribution of diazepam, a highly lipid-soluble drug.

Computer aided diagnosis of acute abdominal pain: a multicentre study

A multicentre study of computer aided diagnosis for patients with acute abdominal pain was performed in eight centres with over 250 participating doctors and 16,737 patients. Performance in diagnosis and decision making was compared over two periods: a test period (when a small computer system was provided to aid diagnosis) and a baseline period (before the system was installed). The two periods were well matched for type of case and rate of accrual. The system proved reliable and was used in 75.1% of possible cases. User reaction was broadly favourable. During the test period improvements were noted in diagnosis, decision making, and patient outcome. Initial diagnostic accuracy rose from 45.6% to 65.3%. The negative laparotomy rate fell by almost half, as did the perforation rate among patients with appendicitis (from 23.7% to 11.5%). The bad management error rate fell from 0.9% to 0.2%, and the observed mortality fell by 22.0%. The savings made were estimated as amounting to 278 laparotomies and 8,516 bed nights during the trial period--equivalent throughout the National Health Service to annual savings in resources worth over 20m pounds and direct cost savings of over 5m pounds. Computer aided diagnosis is a useful system for improving diagnosis and encouraging better clinical practice.

Computer aided diagnosis of acute abdominal pain at Middlesbrough General Hospital

This presentation reports the experience of the surgical house staff and registrars at Middlesbrough General Hospital who used a desk-top computer system to support their clinical diagnosis of acute abdominal pain. The results cover a two year period and are compared with a baseline period of one year. Substantial benefits followed the introduction of the computer-aided diagnostic support system; increased diagnostic accuracy of the whole surgical team, reduction in negative laparotomy rates, earlier surgical intervention for acute appendicitis, reduction in the number of cases of perforated appendicitis and more efficient use of resources. The reasons for these improvements include more thorough collection of data, use of common terminology and an educational element provided by detailed feedback from the computer system.

The acute abdomen: management with microcomputer aid

This paper describes the management consequences of the use of a microcomputer as a special investigation in patients with an acute abdomen. Results in 812 patients seen by 42 junior doctors are compared six monthly and with baseline data from 295 cases from the preceding 2 years. Improvement in diagnostic ability from 48.5% to 71.8% (X2 = 25.8, P less than 0.001) resulted in a fall in negative appendicectomy from 37.5% to 9.71% (X2 = 16.2, P = less than 0.001). Bad management errors were also reduced from 22% to 10% (P = less than 0.01). The number of emergency investigation fell from 4 to 2 and inpatient stay of patients with non-surgical abdominal pain was reduced from 3 to 2 days. These results demonstrate that the use of microcomputers as investigative tools improves the surgical management of patients with acute abdominal pain.

Inhibitory effects of harvested proximal tubular fluid on Jv and delta cNa during acute saline volume expansion in the rat

The present micropuncture experiments were carried out in male Wistar rats during isotonic saline volume expansion (VE) to explore the relative importance of peritubular physical forces and tubular factors on proximal tubular Na transport. Isotonic volume flux, measured by the shrinking drop technique was reduced from 3.53 +/- 0.09 X 10(-4) . mm3 . mm-2 . s-1 with the artificial fluid to 1.79 +/- 0.1 with harvested autologous proximal tubular fluid (HTF) (49%), but only to 2.77 +/- 0.1 (78% of control) with artificial tubular solution (AS), both during volume expansion. delta cNa was reduced from a control of 18.0 +/- 2.2 mmol . kg-1 -14.5 +/- 2.0 with AS (81%) and 10.0 +/- 2.4 with HTF (56%) during VE. Thus both isotonic volume flux as well as delta cNa were reduced to the same degree by saline VE. These results and those obtained previously with mannitol-saline VE, indicate the presence of a factor in harvested proximal tubular fluid of volume expanded rats which inhibits sodium and water transport independent of peritubular osmolarity.

Phosphate uptake by superficial and deep nephron brush border membranes. Effect of the dietary phosphate and parathyroid hormone

Dietary phosphate restriction and acute parathyroidectomy in rat are known to be associated with a selective increase in phosphate uptake by renal cortical brush border membranes (BBM). Conversely, phosphate loading and parathyroid hormone (PTH) administration result in a decrease of this uptake. In the present study, we investigated whether the response of the membrane to these various stimuli implies similar or different modifications of the kinetic properties of this membrane, whether these modifications affect one or both of the two systems of phosphate transport previously described, whether both superficial and deep nephron populations are involved, and whether the two stimuli: dietary phosphate, and parathyroid activity, are additive or not. Kinetic studies of phosphate (PO4) uptake by BBM vesicles were performed in seven groups of rats: control (N), acutely thyroparathyroidectomized (TPTX), PTH loaded (PTH), phosphate loaded (P+), phosphate depleted (P-), phosphate depleted with acute thyroparathyroidectomy (P-TPTX), and phosphate depleted-PTH loaded (P-PTH). In each of these experimental conditions, superficial and deep nephrons were investigated. Results indicated that 1. BBM from deep nephrons present a greater capacity for PO4 transport than those from superficial nephrons; 2. Whereas a dual system of PO4 uptake is observed in superficial BBM, deep BBM present only one single system; 3. Phosphate in the diet influences PO4 uptake by BBM to a greater extent in the deep than in the superficial nephrons; 4. PTH status on the contrary, equally influences both populations; 5. TPTX does not significantly enhance PO4 uptake in phosphate depleted rats; however, PTH loading curtails this uptake; 6.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of temperature and pH on phosphate transport through brush border membrane vesicles in rats

The kinetics of sodium gradient dependent phosphate uptake by the renal brush border membrane vesicles of the rat have ben studied under various conditions of temperature and pH. From 7 to 30 degrees C the Lineweaver-Burk plots are linear, and the apparent Km progressively increases from 54 to 91 microM. Above 30 degrees C, the apparent Km continues to increase to reach 135 microM at 40 degrees C, but a break is observed in the Lineweaver-Burk plots at the substrate concentration of 300 microM. The existence of this break, confirmed by the Eadie-Hofstee plot supports the hypothesis of a dual mechanism of phosphate transport, one for low concentrations of substrate with a Km of 100 microM and the other for high concentrations with a Km of approximately 240 microM. When the two components of the Eadie-Hofstee plot are analyzed according to a nonlinear regression program, these two values of Km become 70 microM and 1.18 mM, respectively. The Vmax continuously increases with temperature. However, the Arrhenius plot (In Vmax vs. 1/TK) shows an abrupt discontinuity at 23 degrees C. pH experiments were performed at 35 degrees C. In the absence of a proton gradient, increasing the pH from 6.5 to 7.5 and 8.5 decreases the apparent Km from 341 to 167 and 94 microM, respectively. When only the divalent form of phosphate is considered as the substrate, the apparent Km does not vary anymore with the pH and remains around the mean value of 105 microM. The uniformity of the apparent Km for the total phosphate uptake, when only the divalent phosphate is considered as being the substrate, suggests that this divalent form is the only one which is transported. Whatever the substrate considered, total phosphate or divalent phosphate, the highest Vmax is obtained at pH 7.5 which probably approximates the optimum pH inside the vesicles for the phosphate uptake.

Pichinde virus-specific cell-associated suppression of primary footpad swelling in an inbred strain of Syrian hamsters

Pichinde virus causes a lethal disease after i.p. inoculation of adult MHA hamsters; other strains of Syrian hamsters are resistant to this lethal infection. During studies of cell-mediated immune responses to Pichinde virus, it was noted that MHA hamsters survived infection when the virus was given in the footpad. However, unlike the resistant LSH and LVG strains of hamsters, the MHA hamsters did not manifest a footpad swelling response. Failure of the MHA hamster to respond to a footpad inoculation of Pichinde virus was shown to be virus-specific and appeared to be mediated by a cell-associated suppressor mechanism.

Pichinde virus-specific cell-associated suppression of primary footpad swelling in an inbred strain of Syrian hamsters

Pichinde virus causes a lethal disease after i.p. inoculation of adult MHA hamsters; other strains of Syrian hamsters are resistant to this lethal infection. During studies of cell-mediated immune responses to Pichinde virus, it was noted that MHA hamsters survived infection when the virus was given in the footpad. However, unlike the resistant LSH and LVG strains of hamsters, the MHA hamsters did not manifest a footpad swelling response. Failure of the MHA hamster to respond to a footpad inoculation of Pichinde virus was shown to be virus-specific and appeared to be mediated by a cell-associated suppressor mechanism.

The effects of pH on the affinity of pirenzepine for muscarinic receptors in the guinea-pig ileum and rat fundus strip

1 Dose-ratios obtained with pirenzepine on the guinea-pig ileum at 30 degrees C are indistinguishable from those obtained at 37 degrees C. 2. In 0.1 M NaCl at 37 degrees C the pKa of pirenzepine for the loss of its last ionizable proton is 8.2. The ionization of pirenzepine is therefore markedly affected by changes in pH in the physiological range. 3 In experiments with pirenzepine on guinea-pig ileum and rat fundus made over a range of pH, the dose-ratio increases with the proportion of the protonated form present. As expected, the slope of the graph of dose-ratio against proportion protonated depends on the concentration of antagonist. The changes in pH produce only small effects on dose-ratios obtained with pirenzepine monomethiodide. These effects of pH can account for some of the differences between estimates of the affinity of pirenzepine. 4 The logarithm of the affinity constant of the protonated form of pirenzepine for the receptors in guinea-pig ileum is estimated to be 6.93, compared with 6.94 for the receptors in rat fundus. However, for the non-protonated form the values appear to be below 5 for the ileum compared with about 6.4 for the rat fundus.

Chemical pulmonary burn injury and chemical intoxication

Two large groups of patients with chemical pulmonary burns who sustained their injuries in the same environment were presented. Data from the blaze smoke analysis of two imitative experiments which were performed under the same conditions as were present when these patients sustained their burns showed a high concentration of carbon monoxide of 35700-571400 ppm and multivariable components of chemicals. The environmental conditions, the clinical course, laboratory findings and blaze analysis clearly demonstrated the close relationship between chemical pulmonary burn injury and chemical intoxication which increased the difficulty in treatment. Ideally, the initial treatment at the site of the fire is the application of 100 per cent oxygen in high flow by mask, and temporary artificial hyperventilation after hospitalization will give a satisfactory result if the fire victim suffers severe carbon monoxide poisoning. In order to treat chemical intoxication in the patient with chemical pulmonary burns successfully, we have adopted a regimen of 'over-loading fluid resuscitation', together with diuretics and positive end expiratory pressure (PEEP) under the monitoring of central venous pressure.

Acute myelogenous leukemia with megakaryocytic myelosis

A case of acute myelogenous leukemia terminating in megakaryocytic myelosis is reported. There was a severe, apparently neoplastic proliferation of megakaryocytes so different from that seen in acute granulocytic leukemia or myelofibrosis that a diagnosis of acute megakaryocytic myelosis was warranted. The clinical and pathologic findings of the case are presented in detail. The literature of this extremely rare hematologic disease is reviewed, and differentiation from chronic and malignant myelosclerosis is discussed.

The prevalence and nature of back pain in an industrial complex: a questionnaire and radiographic and HLA analysis

A questionnaire relating to presence and nature of back pain was distributed to all 10,150 employees (59% men) of an industrial complex. The questionnaire was returned by 2892 subjects (65% men). Of these, 1880 (65% of responders or 19% of total) reported a history of back pain. One hundred twenty-four described their back pain as insidious in onset, persisting for at least three months, developing at less than 40 years of age, being associated with morning stiffness, and showing improvement with exercise. Three hundred sixty-seven subjects scored four of these five features. Pelvic radiographs of 342 persons were available for blind evaluation. Sixteen patients (12 men) were shown to have definite ankylosing spondylitis (Grade III or IV sacroiliitis or HLA B27-associated Grade II sacroiliitis). Only one of these persons was known to have spondylitis. The majority of these symptomatic patients had been seen by both medical and nonmedical practitioners.

Mixed agglutination in microtiter U-trays

The principle of mixed agglutination with cell cultures was applied to those cells which could not be obtained as monolayer cell cultures. Artificial monolayers of freshly isolated cells from various tissues were prepared in poly-L-lysine-coated wells of a microtiter U-tray. By means of this technique, murine alloantigens, H-2 private specificities and Thy-1 antigens were demonstrated on cells from thymus, brain, spleen, kidney and liver. Ia.2 antigen was detected on splenocytes but not on thymocytes or fibroblast L cells. Evidence was also presented that HLA A and B locus antigens could be demonstrated on human thymocytes. Sensitivity of this test was shown to be at least 100 times higher than that of the standard lymphocytotoxicity test for detection of HLA antigens.

Ventricular preexcitation syndrome. Accessory left atrioventricular connection and rhabdomyomatous myocardial fibers

A necropsy study of the heart of a 16-year-old girl with ventricular preexcitation syndrome and supraventricular tachycardia showed an accessory left atrioventricular connection partially within the mitral valve. Both the accessory pathway and the ventricular musculature showed multiple foci of cardiac muscle fibers with rhabdomyomatous features having the characteristic appearance of rhabdomyomatosis. The case is discussed in the context of a literature review of necropsy findings in cases of ventricular preexcitation.

Biosynthesis of diacylglycerols by rat intestinal mucosa in vivo

The biosynthesis of diacylglycerols was studied in rat intestinal mucosa during in vivo absorption of a low molecular weight fraction fraction of butter oil and of the corresponding medium and long chain fatty acids. The experimental fat solutions were given by stomach tube to the animals after a 24-h fast and mucosal scraping were collected 3 h later. The lipids were isolated and the acylclycerols determined by combined thin-layer chromatography gas-liquid chromatography techniques and stereospecific analyses. Free fatty acid feeding led mainly to sn-1,2-diacyl-glycerols, which contained exogenous and endogenous fatty acids. During triacylglycerol feeding, both sn-1,2-and sn-2,3-diacylglycerols were recovered in significant amounts from the intestinal mucosa. The composition of the sn-2,3-diacylglycerols corresponded to that with exogenous fatty acids but the sn-1,2-diacylglycerols clearly contained both exogenous and endogenous fatty acids. In all cases it was possible to isolate endogenous sn-1,2-diacylglycerols made up largely of species with linoleic and arachidonic acids in the 2 position and palmitic and stearic acids in the 1 position, which apparently were not converted to triacylglycerols. The in vivo reacylation of 2-monoacylglycerols via both sn-1,2- and sn-2,3-diacylglycerols is in agreement with similar findings in vitro with everted sacs of rat intestinal mucosa.

Inhibition of RNA synthesis by acetyl salicylate and actinomycin D during early development in the mouse

Experiments were designed to ascertain and compare the effects of acetyl salicylate and actinomycin D on RNA synthesis in mouse oocytes in vitro and in vivo. After exposure to the drugs the effects on RNA synthesis were measured by incorporation of [3H]uridine and autoradiography. The results indicate that acetyl salicylate inhibits RNA synthesis in the treated oocytes as does actinomycin D. The only difference in the effects of these two drugs is that salicylate inhibits RNA synthesis to a much lesser degree than does actinomycin D. Effects from a short exposure to salicylate may be reversible; the same effects with actinomycin D cannot be reversed. In utero exposure of the female fetus may lead to partial or total sterility (depending on the dose and time of exposure) of that fetus and/or abnormal development of the progeny from those mice (F2). These results suggest that RNA synthesis in early oogenesis is a vital part of later development of the oocytes in adult mouse ovary. Inhibition of RNA may be one of the causes of malformations and sterility.