Cell loss and class distribution of TH-I cells in the substantia nigra of the neurological mutant, weaver

Eight-week-old homozygous weaver mutant mice and littermate wildtype controls were perfused with a buffered acrolein and paraformaldehyde solution. The brains were subsequently removed, blocked and sectioned on a vibratome. Representative sections through the midbrain were incubated overnight with an antibody for tyrosine hydroxylase. Visualization of the antibody was achieved using the peroxidase-antiperoxidase technique. The immunoreactive cells in the substantia nigra were examined to determine the subclasses of cells that are affected when dopaminergic neurons are lost in these mutants. Class distributions were determined and the data were subjected to chi 2 analyses. The results indicate a significant loss of tyrosine hydroxylase-immunoreactive cells in both the pars compacta and pars lateralis that is dependent upon the group and the region being studied. In addition, distributional shifts within the classes of labeled neurons suggest that there is an increase in the small neurons over the expected numbers in both divisions of the substantia nigra.

Review of endosseous implants for partially edentulous patients

The scientific documentation of the biologic acceptability of the Brånemark osseointegrated implant has increased the interest in implants. This documentation was done on completely edentulous patients and therefore is not necessarily transferable to partially edentulous patients. Demographic studies indicate an increased need for implant restoration, yet clinical documentation of the effectiveness of implants in the partially edentulous is not nearly as strong as for the completely edentulous patient. There is a great need for well-designed research to compare prosthodontic materials and techniques. This review summarizes the literature on implants in the partially dentate mouth.

Benzodiazepine dependency discontinuation: focus on the chemical dependency detoxification setting and benzodiazepine-polydrug abuse

Benzodiazepines are commonly encountered in both psychiatric and chemical dependency treatment settings. However, in the chemical dependency setting, benzodiazepines are most frequently used as secondary drugs of abuse, and are most often found within a polydrug use pattern. Benzodiazepine use by the drug-abusing population consists of the combined use of benzodiazepines with other psychoactive drugs. They are used to medicate cocaine toxicity, as a secondary or tertiary drug to boost the effects of alcohol or heroin, and by those who have developed tolerance and dependence to sedative-hypnotic drugs. The presence of an anxiety disorder, a family history of addiction, or benzodiazepine polydrug use will significantly affect the type of withdrawal a patient will experience and its treatment course. Medical procedures accepted for benzodiazepine discontinuation include (1) graded reduction; (2) substitution of a long-acting benzodiazepine; and (3) phenobarbital substitution.

Removable prosthodontics research--quo vadis?

The need to improve removable prosthodontic treatment through research has not diminished. Most recent research reports in prosthodontics are in fixed prosthodontics, indicating a declining interest in removable prosthodontics. A survey of dental schools in the United States and Canada reveals that the financial support for research in removable prosthodontics is a mean of $42,500 per year. Present research is not directed toward solving the major problems in removable prosthodontics. The key to making progress in removable prosthodontic research is to interest capable trainees in securing the necessary basic science and clinical training. Adequate financial support is then needed to conduct the research.

Natural killer lymphocyte blast crisis of chronic myelogenous leukemia

We describe for the first time a case report documenting a chronic myelogenous leukemia (CML) patient who developed a blast crisis of natural killer (NK) lymphocytes. Many of the blasts exhibited large granular lymphocytic (LGL) morphology. Single parameter immunophenotyping results determined that the granulated as well as the agranulated blast cells were NK lymphocytes (CD45, NKH1, CD2, LEU 17, and CD16 positive; CD3, CD8, and LEU 7 negative). Dual parameter flow cytometric testing also determined that some of the blasts expressed the CD11b and CD11c markers as reported for some types of NK lymphocytes. Approximately 10% of the cells were in the S phase of the cell cycle as determined by a modified Vindelov DNA content analysis test and may theoretically reflect some of those cells expressing CD11b and CD11c. The cells did not express in vitro NK lymphocyte functional activity against a K562 target and therefore similar to other reported cases of presumably immature NK lymphocytic leukemias. The NK lymphocyte blast crisis was successfully treated with vincristine and prednisone. The patient's disease eventually relapsed and transformed to a progenitor stem cell before she died (CD45, 13, CD38, and CD34 positive). The flow cytometric immunophenotyping results contributed significantly as an important adjunct in determining the appropriate diagnosis, helping to select the type of therapy, and monitoring the patient with this unusual type of blast crisis.

Federal guidelines for marijuana screening should have lower cutoff levels. A comparison of results from immunoassays and gas chromatography-mass spectrometry

Federal guidelines for urine marijuana testing use a screening cutoff of 100 ng/mL and a confirming cutoff of 15 ng/mL. We tested 75 urine samples with two different immunoassays with cutoff points of 100 and 20 ng/mL. The same samples were also analyzed with gas chromatography-mass spectrometry. At the government recommended cutoff levels for screening and confirming, test sensitivity was 47% and specificity was 91%. With a screening cutoff of 20 ng/mL confirmed at 5 ng/mL, test sensitivity was 88% and specificity was 94%. We suggest adoption of these lower cutoff levels.

Criteria for success of osseointegrated endosseous implants

Because of the proliferation of implant systems, a set of criteria for implant success based on scientific investigations is essential. A review of the literature and the analysis of the results indicate that six criteria are supported as valid for determining the clinical success of endosseous dental implants. These criteria are proposed for use in clinical investigation on implants.

Postoperative adjuvant chemotherapy and radiotherapy for cancer of the large bowel and rectum

Forty patients with invasive regional-stage adenocarcinoma of the large bowel and rectum received adjuvant postoperative chemotherapy combined with doses of radiation below the maximal tissue tolerance level. This treatment was reserved for patients with stage B2, C1, and C2 lesions, with only two exceptions. The treatment was well tolerated. It appeared to result in a longer disease-free interval when compared with population-based results for patients with sigmoid cancer who had surgery alone. Our results paralleled those of the Gastrointestinal Tumor Study Group (GITSG) for combined adjuvant therapy of rectal cancer, who also indicated an advantage for long-term survival. Patients who received additional extended chemotherapy had at least the same percentage of favorable outcomes. Tumors above the peritoneal reflection also appeared to share the same improved results. We believe a multicenter randomized study should be performed to evaluate this group of patients.

Considerations in using psychotropic medication with dual diagnosis patients in recovery

This article addresses some of the issues that arise when chemically dependent patients with coexisting psychiatric disorders require medication. A history of chemical dependence may alter prescribing practices, as certain medications may have a higher abuse potential or may enhance the danger of relapse to the primary drug of abuse. Recovering patients have complex attitudes and feelings toward medications that need to be explored, particularly as they affect compliance with prescribed regimens. Issues arising in the treatment of anxiety disorders, depression, and attention deficit disorders are discussed. Guidelines are provided for therapists working with prescribing physicians, and for handling problems that may arise in conjunction with 12-Step program participation.

Heavy cocaine use by adolescents

Adolescents are susceptible to becoming cocaine users. Twenty-eight teenagers in a drug rehabilitation program were identified as heavy cocaine users and questioned about their experiences. They reported family conflict leading to running away (86%), school drop-out (24%) and delinquent behaviors such as stealing (96%) and vandalism (57%). Cocaine use started at 14 years for 21%, with progression from onset to at least weekly use within eight weeks (54%). Side effects included sleep disturbance (18%) and tolerance to cocaine (25%). Withdrawal was characterized by cocaine craving up to one month later (93%). The majority (96%) were polydrug abusers. Possible causes of teen substance abuse are discussed, and the importance of prevention is emphasized.

Adaptation of a visible light-cured denture base material

The Triad light-cured resin system appears to have potential for making processed record bases for special patients. The close adaptation of this material to the dental cast often results in internal voids and defects. These defects are greatly reduced when a dry cast is used instead of one with a high moisture content. Vacuum-assisted adaptation using a sheet of rubber dam in connection with a vacuum adaptor also results in an improved internal surface. Finger pressure alone is not a dependable method of adaptation.

Heat shock-induced appearance of RNA polymerase II in karyoskeletal protein-enriched (nuclear "matrix") fractions correlates with transcriptional shutdown in Drosophila melanogaster

Heat shock in vivo or brief incubation at moderately elevated temperatures (15 min at 37 degrees C) in vitro is required for the structural stability of proteinaceous karyoskeletal elements purified from Drosophila melanogaster (McConnell, M., Whalen, A. M., Smith, D. E., and Fisher, P. A. (1987) J. Cell Biol. 105, 1087-1098). We have found that the appearance of the two largest subunits of RNA polymerase II in karyoskeletal preparations is promoted by conditions identical to those which promote in vitro stability of karyoskeletal elements overall. Increased levels of polymerase II in karyoskeletal protein-enriched fractions correlate with decreased levels of nucleotide incorporation in nuclear transcription run-on assays. These results are not easily reconciled with the proposal that putative karyoskeletal elements such as the internal nuclear "matrix" are sites of active transcription in vivo.

Quantification of Cholesterol Oxidation Products in a Variety of Foods

Cholesterol oxidation products (COPS) were estimated in a variety of foods by gas chromatography. Substantial quantities of α- and β-epoxide (2 to 46 and 0 to 111 ppm, respectively) and lesser quantities of 7β-hydroxy- and 7-ketocholesterol were found in powdered egg products. Other foods found to contain COPS included dehydrated chicken, turkey and beef (0 to 43 ppm); and Cheddar, Blue, Romano and Parmesan cheese powders (0 to 17 ppm). Powdered infant formulas and dehydrated baby foods displayed several peaks coinciding to COPS but none were confirmed by mass spectroscopy. COPS were either not detected or noted at < 15 ppm in fresh dairy products.

Interconversion of Drosophila nuclear lamin isoforms during oogenesis, early embryogenesis, and upon entry of cultured cells into mitosis

Two isoforms of a single nuclear lamin, distinguishable on one-dimensional SDS-polyacrylamide gels, have previously been identified in Drosophila nuclei during interphase. A third species, designated lamin Dmmit, has now been identified as soluble in extracts of Drosophila tissue culture cells blocked in mitosis by drugs. An apparently identical form is the only lamin species detectable in late-stage egg chambers and early embryos. Phosphoamino acid analyses suggest that the conversion of lamins Dm1 and Dm2 to lamin Dmmit is brought about by a specific rearrangement of phosphate groups rather than by dramatic net changes in the levels of lamin phosphorylation. The residues involved in these phosphorylation/dephosphorylation reactions have been tentatively mapped to a 17.8-kD cyanogen bromide fragment containing amino acids 385-547. This represents a potential "hinge" domain in the lamin structure between the end of coil 2 and the globular COOH terminus. These results have implications for understanding the regulation of nuclear envelope breakdown during mitosis and karyoskeletal dynamics during oogenesis and early embryogenesis.

Levels of serum cholesterol, triglyceride, HDL-cholesterol, apoproteins A-I and B, and plasma glucose, and prevalence of diastolic hypertension and cigarette smoking in Papua New Guinea highlanders

Coronary heart disease (CHD) is rare in Papua New Guinea (PNG) highlanders. Fifty-two men and 69 women randomly selected from three rural communities and a low socioeconomic urban community in the Eastern Highlands Province were assessed for hyperlipidemia, diabetes mellitus, diastolic hypertension and cigarette smoking. There was no significant difference between the findings in the rural and urban groups. The mean fasting levels of serum cholesterol, HDL cholesterol and apoproteins A-I and B were significantly lower (p less than 0.001) than those of rural Australians in a comparative study but the serum triglyceride levels were significantly higher in men less than 30 yr and women less than 40 yr of age. There was no significant difference in the serum cholesterol levels in men and women, and the levels of serum cholesterol and triglyceride did not rise with age. The mean fasting levels of plasma glucose were generally lower in PNG subjects and only two (1.7%) had diabetes mellitus. The proportions of highlanders who had diastolic hypertension or who smoked cigarettes were similar to those of Australian populations generally. The low incidence of CHD in PNG highlanders is probably related to the low serum cholesterol and apoprotein B levels, in turn probably related to their basically vegetarian diet and physically active life-style.

Effect of organ perfusion on renal drug transport. Application to furosemide in the isolated perfused rat kidney

Angiotensin II was used as a probe to study the effect of changes in perfusate flow rate on the renal clearance parameters of furosemide in the isolated perfused rat kidney. Drug studies were performed in three rats with no angiotensin II present in the perfusate (treatment I) and in three rats with a 2.7 ng/min infusion of angiotensin II into the perfusate (treatment II). Furosemide was introduced into the recirculating perfusate at an initial concentration of 3.5 micrograms/ml and was assayed using HPLC. The protein binding of furosemide in perfusate was determined by equilibrium dialysis. Angiotensin II was found to have a dramatic effect on the renal hemodynamics, resulting in a 42% decrease in perfusate flow, a 27% decrease in GFR, and a 25% increase in filtration fraction. Values for the fractional excretion of glucose were very low and consistent, with or without angiotensin II (3.0-3.5%). Although the fraction unbound of furosemide was unchanged between treatments (0.770 for treatment I vs. 0.695% for treatment II), the renal and secretion clearances of furosemide were reduced by about 30% in the presence of angiotensin II. However, if the renal clearance (CLr) was corrected for free fraction (fu) and glomerular filtration rate (GFR) [ER = CLr/(fu.GFR)], there was no difference between the excretion ratio (ER) values of furosemide after the two treatments (29.0 for treatment I vs. 29.6 for treatment II). These results imply that the altered clearance parameters of furosemide are more likely the consequence of a reduction in functional nephron mass rather than a change in intrinsic secretory transport per unit mass of nephron.

Severe exercise hypoxaemia with normal or near normal X-rays: a feature of Pneumocystis carinii infection

To find out whether Pneumocystis carinii pneumonia (PCP) can be detected while still in an early phase by the degree of exercise-induced oxygen desaturation, arterial oxygen saturation was measured by continuous pulse oximetry in patients positive for antibody to the human immunodeficiency virus and clinically suspected of having PCP, in patients with other chest diseases, and in controls. Among patients with proven PCP 94% of those with low arterial oxygen pressures (PaO2) showed desaturation on exercise oximetry, as did 80% of those with a normal oxygen pressure at rest, whereas only 10% of patients with other chest disorders and HIV disease showed significant desaturation.

Kinetics, dynamics, and bioavailability of bumetanide in healthy subjects and patients with congestive heart failure

Four healthy subjects and six patients with congestive heart failure (CHF) were given 3 mg oral and intravenous doses of bumetanide in a random crossover fashion. Bumetanide was analyzed by HPLC, and sodium and potassium was analyzed by flame photometry. Aside from a modest reduction in renal clearance, the kinetics of bumetanide in CHF were similar to those in healthy subjects. The extent of bioavailability was 81%, with a variability of 20% to 25% about the mean for both groups. The cumulative dynamic responses to bumetanide, whether administered orally or intravenously, were essentially the same in each group. Pharmacodynamic modeling showed that there were no significant differences between healthy subjects and patients with CHF in either ER50 (bumetanide urinary excretion rate producing 50% of maximum drug effect) or S (slope), although the baseline effect was 15 times lower in CHF. The maximum effect attributable to bumetanide was twofold higher in healthy subjects and there was a significant correlation between this parameter and creatinine clearance (r = 0.964; p less than 0.001). Overall, these results indicate that a predictable transition from 3 mg intravenous to oral doses of bumetanide is possible in CHF.

Renal transport kinetics of chlorothiazide in the isolated perfused rat kidney

The effect of protein binding on the renal excretion of chlorothiazide was examined in the isolated perfused rat kidney. Drug studies were performed in three rats at 6.00% bovine serum albumin + 0% dextran and in three rats at 0.25% bovine serum albumin + 3.83% dextran. Chlorothiazide was introduced into the recirculating perfusate at an initial concentration of 100 micrograms/ml, and was assayed using high-performance liquid chromatography. Functional viability of the kidney was assessed by measuring the fractional excretion of sodium and glucose, and the glomerular filtration rate. The protein binding of drug in perfusate was determined by equilibrium dialysis. These experimental conditions resulted in an approximate 14-fold increase of percent free (from 5.3-72.0%), and a 3-fold increase of renal (from 1.03-3.30 ml/min) and secretion (from 1.01-2.83 ml/min) clearances. The data were best fitted by a model in which one Michaelis-Menten term was used to describe active transport, and secretion was dependent upon free concentrations of chlorothiazide in the perfusate. The maximum velocity of secretion (Vm = 85.6 micrograms/min) and Michaelis constant (Km = 2.1 micrograms/ml) of chlorothiazide was estimated using a nonlinear least-squares regression program. These results suggest that for compounds of low renal extraction, free drug concentrations are the driving force for carrier-mediated tubular secretion.