Biomedical subjects

A Myers

Publications and source records attributed to A Myers.

At least 55 records · Page 3Linked to original sources

PubMed1995

Sweat gland carcinoma in a human immunodeficiency virus-infected patient.

Eccrine (sweat gland) carcinoma is a rare form of skin cancer that may be locally destructive. It is known to recur after resection and can metastasize to regional or distant lymph nodes. There have been two reported cases in association with patients immunocompromised as the result of organ transplantation (I. Penn: Prog Allergy. 37: 259, 1986). We report here the first case of sweat gland carcinoma in a patient infected with the human immunodeficiency virus.

Acquired Immunodeficiency Syndrome↗

PubMed1995

Epidemiology of hip fractures among the elderly. Risk factors for fracture type.

A study was undertaken in September 1988 of 169 patients who were > 50 years of age receiving care for hip fractures at 4 university-affiliated hospitals during a 2-year period. Demographics, medical history, cognitive function, mobility, and environmental factors surrounding the hip fractures were ascertained by patient or proxy interview and review of medical records. These were then related to the type and severity of hip fracture. Eighty-three (49%) patients had intertrochanteric fractures, 23 (14%) had subtrochanteric fractures, and 63 (37%) had intracapsular fractures. Walking versus standing, sitting, or getting up at the time of fracture (relative odds = 3.2, p = .041), and no mobility difficulty versus some mobility difficulty (relative odds = 5.2, p = .047) were associated with increased comminution in intertrochanteric or subtrochanteric fractures. The location of the fracture occurrence (indoor versus outdoors) was associated with greater displacement in intracapsular fractures (relative odds = 6.7, p = 0.021). Only 2 of 169 patients had spontaneous hip fractures, defined as hip pain that preceded the fall. Because spontaneous fractures are rare, efforts directed toward preventing falls would be expected to decrease the incidence of hip fractures. Future possibilities include the development of protective garments that can reduce impact loading to the hip during a fall.

Accidental Falls↗

PubMed1994

Interactions between the bud emergence proteins Bem1p and Bem2p and Rho-type GTPases in yeast.

The SH3 domain-containing protein Bem1p is needed for normal bud emergence and mating projection formation, two processes that require asymmetric reorganizations of the cortical cytoskeleton in Saccharomyces cerevisiae. To identify proteins that functionally and/or physically interact with Bem1p, we screened for mutations that display synthetic lethality with a mutant allele of the BEM1 gene and for genes whose products display two-hybrid interactions with the Bem1 protein. CDC24, which is required for bud emergence and encodes a GEF (guanine-nucleotide exchange factor) for the essential Rho-type GTPase Cdc42p, was identified during both screens. The COOH-terminal 75 amino acids of Cdc24p, outside of the GEF domain, can interact with a portion of Bem1p that lacks both SH3 domains. Bacterially expressed Cdc24p and Bem1p bind to each other in vitro, indicating that no other yeast proteins are required for this interaction. The most frequently identified gene that arose from the bem1 synthetic-lethal screen was the bud-emergence gene BEM2 (Bender and Pringle. 1991. Mol. Cell Biol. 11:1295-1395), which is allelic with IPL2 (increase in ploidy; Chan and Botstein, 1993. Genetics. 135:677-691). Here we show that Bem2p contains a GAP (GTPase-activating protein) domain for Rho-type GTPases, and that this portion of Bem2p can stimulate in vitro the GTPase activity of Rho1p, a second essential yeast Rho-type GTPase. Cells deleted for BEM2 become large and multinucleate. These and other genetic, two-hybrid, biochemical, and phenotypic data suggest that multiple Rho-type GTPases control the reorganization of the cortical cytoskeleton in yeast and that the functions of these GTPases are tightly coupled. Also, these findings raise the possibility that Bem1p may regulate or be a target of action of one or more of these GTPases.

Adaptor Proteins, Signal Transducing↗

PubMed1993

First use of G-CSF in chlorpromazine-induced agranulocytosis: a report of two cases.

Chlorpromazine-induced agranulocytosis is an uncommon disorder associated with a high frequency of fatality. We describe two patients with chlorpromazine-induced granulocytosis in whom granulocyte colony stimulating factor (G-CSF) administration enhanced the speed of neutrophil recovery. No toxicity was noted with G-CSF and both patients made a successful recovery. We propose there is a role for such cytokine therapy in patients with life-threatening agranulocytosis in order to speed the recovery of neutrophils.

Adult↗

PubMed1993

Low back injuries among home health aides compared with hospital nursing aides.

Data were collected from all incident reports of low back injury during 1984-1986 among nursing aides at one hospital and home health aides at two agencies in the Baltimore-Washington area. Respective rates of injury were 5.9/100 FTE's and 15.4/100 FTE's (p < 0.001). A majority of injuries occurred during patient-related, planned activities and without the use of lifting equipment. Forty percent of the events occurred at the bedside. Eighty-eight percent of home health aides were working alone compared with 39 percent of NAs. Ergonomic interventions may be an effective strategy to reduce injuries, since 50 percent of the events involved lifting and pushing/pulling activities.

Accidents, Occupational↗

PubMed1992

CT-stereotactic fibrinolysis of spontaneous intracerebral hematomas.

CT-stereotactic fibrinolysis is an effective alternative to surgical and conservative therapies for intracerebral hematoma. The method consists of stereotactically puncturing and partially evacuating the hematoma. After fibrinolysis using urokinase, the residual hematoma is completely evacuated through a catheter inserted in the cavity of the hematoma. The operation is usually performed under local anesthesia. Stereotactic methods are safer and less invasive than other methods. Since October 1985, a total of 85 patients have been treated with this method in the Department of Stereotaxy and Neuronuclear Medicine at the University of Freiburg Medical School. Although 25 patients died (29.4%) during the mean follow-up period of 20 months, only 16 (18.8%) died in the acute postoperative phase or within the first 60 days after evacuation. Eighteen patients (21.2%) had died six months after the operation. The quality of life of the 60 surviving patients, as measured on the Karnofsky Scale at follow-up, was very good to good in 70% and moderate in 23.3%. Only 6.7% of the patients were so disabled that they required special care and assistance or had to be placed in a nursing home. The long-term results are thus very encouraging.

Cause of Death↗

PubMed1992

Effect of N-substituted arginine compounds on blood pressure in anesthetized rats.

Inhibition of endothelium-dependent relaxation by NG-monomethyl L-arginine (L-NMMA) and its reversal by excess L- but not D-arginine is used to support the hypothesis that the endothelium-derived relaxing factor (EDRF) is generated exclusively from the metabolism of L-arginine. However, in freshly isolated vascular tissues, L-arginine is a poor vasodilator when compared to the N-substituted arginine compound, N alpha-benzoyl L-arginine ethyl ester (BAEE). Here, we show that such N-substituted compounds are potent hypotensive agents in anesthetized rats. In contrast, L-arginine elicits hypotensive effect only at higher concentrations (greater than 100 mg/kg). This effect of L-arginine is not antagonized by L-NMMA. Furthermore, D-arginine, L-homoarginine and L-lysine also have hypotensive effects at these concentrations. Indomethacin treatment partially attenuates the hypotensive effects of the basic amino acids. In contrast, the hypotensive effect of BAEE is antagonized by L-NMMA in a dose-dependent manner and by methylene blue, which is an inhibitor of soluble guanylate cyclase. In addition, substitution at the arginine moiety determines the hypotensive effect. When the amino acid glycine is inserted between the benzoyl group and arginine as in benzoyl-glycine-arginine, significant attenuation of the hypotensive effect is observed. These data demonstrate that compounds such as BAEE generate an EDRF-like agent in vivo and basic amino acids such as L-arginine elicit hypotension at concentrations above 100 mg/kg by mechanisms other than the generation of EDRF.

Amino Acids↗

PubMed1991

Immunogenetic prediction of pulmonary fibrosis in systemic sclerosis.

75 systemic sclerosis patients were independently tested for pulmonary fibrosis, autoantibodies, and MHC class II genes. 24 of 42 (57%) patients with pulmonary fibrosis had either HLA DR3/DRw52a or anti-Scl-70 vs 2 of 33 (6%) patients without pulmonary fibrosis. The presence of DR3/DRw52a or anti-Scl-70 gives a relative risk of 16.7 for the development of pulmonary fibrosis in a patient with scleroderma--a risk substantial enough to require careful monitoring of these patients and treatment at an early stage of disease.

Autoantibodies↗

PubMed1991

Rheumatic symptoms and human immunodeficiency virus infection. The influence of clinical and laboratory variables in a longitudinal cohort study.

The present study was designed to prospectively evaluate the frequency of rheumatic symptoms in a cohort of patients infected with the human immunodeficiency virus (HIV), to examine the relationship between such findings and a variety of clinical and epidemiologic variables, and to evaluate the impact of rheumatic symptoms on the natural history of the HIV infection. One hundred seventeen patients were evaluated over a mean of 24.6 months (range 0.5-85 months). Cumulatively, 1.7% had Reiter's syndrome, 1.7% had psoriatic arthritis, and 11.1% had various forms of oligoarticular/monarticular or polyarticular arthritis. The majority of the rheumatic symptoms developed during the longitudinal evaluation and predominantly affected patients with clinically advanced HIV infection. Patients with articular disease tended to have more progressive HIV infection and were more likely to experience disease progression to clinical acquired immunodeficiency syndrome or death. Our data suggest that the occurrence of rheumatic symptoms in the presence of HIV infection is not uncommon and tends to develop over time, in the setting of clinically advanced retroviral infection. Furthermore, the presence of rheumatic symptoms may be a sign of a poor prognosis for patients with HIV infection.

Adult↗

PubMed1991

Functional analysis of the 3'-terminal sequence of the maize controlling element (Ac) by internal replacement and deletion mutagenesis.

Using deletion analysis of the Ac transposable element, we have shown that replacement of internal sequences from base pairs 181-3559 does not abolish transposition. We have done sequential deletion analysis of the 3'-end of the Ac element and found that deletion of the major transposase binding sites (AAACGG) abolishes transposition. But, surprisingly, we found a 3'-terminal deletion of the transposase binding sites which also contained a 71-bp internal sequence between base pairs 3559 and 3630 retained transposition ability. This 71-bp internal sequence did not have a transposase (ORFa) binding motif. These data suggest that two different domains may be involved in the minimal sequence necessary for transposition. Finally, we have identified functional prokaryotic promoter sequences and ARS sequences within the 5' and 3'-termini of Ac, but cannot ascribe any function to these sequences.

Base Sequence↗

PubMed1991

A case/control study of adult haematological malignancies in relation to overhead powerlines.

A population based case control study of adult haematological malignancy and distance from, and magnetic fields associated with, overhead (OH) power lines has been carried out in the North West and Yorkshire regions of England. Three-thousand, one hundred and forty-four cases with histologically proven disease were entered into the study. One control per case, matched for age, sex, year of diagnosis and health district of residence, was selected from hospital discharges. Seven per cent of cases and controls lived near to OH power lines as defined by the study protocol. The measure of exposure used was the calculated magnetic field strength at each of these addresses due to maximum load currents carried by OH power lines in the 5 years preceding diagnosis. The odds ratio (OR) for living within 50 m of an OH line was 1.29 with a 95% Confidence Interval (CI) of 0.99-1.68 but a chi 2 test for trend with distance was not statistically significant. The analysis of calculated magnetic fields, did not produce any statistically odds ratios. The OR for magnetic fields greater than or equal to 0.1 mG was 1.03 (95% CI 0.81 1.32). Analysis of magnetic fields greater than or equal to 3.0 mG gave an OR of 1.87 (95% CI 0.79 4.42), but this result is based on small numbers. No evidence was found for confounding by the type of dwelling which was used as a partial surrogate for socio-economic status.

Age Factors↗

PubMed1991

srfA is an operon required for surfactin production, competence development, and efficient sporulation in Bacillus subtilis.

The srfA locus of Bacillus subtilis is defined by a transposon Tn917 insertion and is required for production of the peptide secondary metabolite surfactin. The srfA locus was isolated by cloning the DNA flanking srfA::Tn917 insertions followed by chromosome walking. The cloned region is an operon of over 25 kb which covers the transcription initiation region but not the intact 3' end of srfA. csh-293, which was previously identified as a Tn917lac mutation that impairs competence development and causes a conditional defect in sporulation, was known to be located in the vicinity of the srfA locus within the B. subtilis genome. The csh-293::Tn917lac mutation was discovered to cause a defect in surfactin production and was shown to be located in the srfA operon by its cotransformation with srfA mutations and by Southern hybridization analysis. Insertion mutations in srfA, created by the chromosomal integration of plasmids bearing overlapping srfA DNA fragments, were examined for their effects on surfactin production, competence, and sporulation. All three processes were found to require the intact 5' half of the srfA operon, whereas the 3' half of srfA was found to be required for sporulation and surfactin production but not competence. These experiments show that srfA gene products function in B. subtilis cell specialization and differentiation.

Amino Acid Sequence↗

PubMed1991

A comparison of buccal nitroglycerin and sublingual nitroglycerin in the prophylaxis and treatment of exertional (situation-provoked) angina pectoris.

Suscard is a buccally administered formulation which provides rapid introduction of nitroglycerin directly into the systemic circulation and, by virtue of its sustained-release properties, may confer protection against anginal attacks for several hours. Its efficacy has been established in angina pectoris and more recently its usefulness has been extended to include the management of unstable angina and acute heart failure. Buccal nitroglycerin combines the possibilities of short-term treatment and more extended prophylaxis. In a multicentre double-blind study the efficacy of buccal nitroglycerin and sublingual nitroglycerin were compared in patients with proven chronic stable exercise-induced angina as regards anginal attacks and capacity for physical activity. The conclusion is that the two formulations of nitroglycerin have a comparable effect in the treatment of acute attacks of angina pectoris. Buccal nitroglycerin has many advantages when used prophylactically. This is documented by less frequent anginal attacks and a more prolonged duration of effect resulting in an increased physical activity.

Administration, Buccal↗

PubMed1991

[Stereotactic evacuation and early rehabilitation in space-occupying cerebral hemorrhage].

The choice of treatment in intracerebral hematoma remains controversial as long as there are no prospective, randomized trials from multiple centers. Recent experiences showed a lower mortality rate after stereotactic evacuation of intracerebral hematoma. However according to the present study (60 patients) the quality of survival and duration of hospital stay seems to be dependent on early and intensified rehabilitation and physiotherapy.

Cerebral Hemorrhage↗

PubMed1990

Calcium channel blocker toxicity.

A retrospective review was conducted of all patients who were reported to a regional poison control center after "overdose" of a calcium channel blocker during a two-year period (1987 and 1988). An analysis of 91 patient cases is presented after excluding allergic reactions, cases involving coingestants, and patients lost to follow-up. Patients who developed any symptoms after ingestion were defined as manifesting toxicity. There were 38 cases of verapamil ingestion with toxicity developing in 18 patients. The mean nontoxic dose was 320 mg, whereas the mean toxic ingestion was 3.2 g. Nine patients became hypotensive, 13 developed conduction system abnormalities (sinus node suppression, atrioventricular nodal block, or bundle branch block), and 11 manifested arrhythmias. Ten developed neurological symptoms. There were 31 cases of nifedipine ingestion with toxicity developing in seven patients. The mean nontoxic dose was 19 mg, while the mean toxic ingestion was 340 mg. Four patients were hypotensive, only one developed cardiac conduction abnormalities, and four developed arrhythmias. Three had neurological symptoms. There were 24 cases of diltiazem ingestion with only minor toxicity developing in four patients. There was no statistically significant difference in the frequency of hypotension, arrhythmias, or neurological symptoms in patients who overdosed with verapamil as compared with nifedipine (by Fisher's exact test). However, conduction system abnormalities were more common with verapamil ingestion (P less than .05). Toxic manifestations after diltiazem over-dose were uncommon in our study. Eighteen of the 29 patients who developed toxicity required treatment in excess of gastrointestinal decontamination. Calcium was administered to 14 patients and was helpful in five.

Adolescent↗

PubMed1990

Childhood cancer and overhead powerlines: a case-control study.

A case-control study has been carried out to examine the occurrence of childhood cancer in relation to the proximity of overhead power lines to a child's home address at birth and to the calculated magnetic field at the address. The study included 374 cases diagnosed in the Yorkshire Health Region between 1970 and 1979, together with 588 matched controls. Magnetic-field strengths at the birth addresses due to the load currents of overhead power lines were calculated on the basis of line-network maps and load records. The results indicate no association between the occurrence of childhood malignancies and either the proximity or the magnetic fields of overhead lines, although the statistical power of the study was limited by the small numbers of children living close to overhead power lines.

Adolescent↗

PubMed1990

Aggressive non-Hodgkin's lymphomas in AIDS: the University of Colorado experience.

The authors performed this retrospective study to further investigate the relationship between non-Hodgkin's lymphoma (NHL) and the Acquired Immunodeficiency Syndrome (AIDS). From January 1984 through December 1987 all cases of AIDS and NHL diagnosed at the University of Colorado affiliated hospitals were identified and submitted to chart review. Twenty-five patients fulfilled criteria for the diagnosis of AIDS and 24 had biopsy-proven NHL, an additional patient met criteria for the diagnosis of primary central nervous system lymphoma and was included in the analysis. All patients had known risk factors for the development of AIDS. Of the biopsy proven tumors, 23 were categorized as high grade. Most patients (68%) presented with stage IV disease and 92% with extra nodal involvement. Median survival was 5 months and the cause of death was most often progressive lymphoma and/or opportunistic infections. These data are similar to previously published series. Clinical trials to evaluate effective treatment are warranted.

Acquired Immunodeficiency Syndrome↗

PubMed1989

Lupus nephritis: efficacy of monthly pulse therapy with intravenous methylprednisolone.

Fourteen patients with severe systemic lupus erythematosus and nephritis were treated with high-dose intravenous methylprednisolone (IVMP) pulse therapy. Six patients (group 1) received one or two courses of 1 gm of IVMP when they were acutely ill with rapidly progressive renal failure or with multisystemic disease. All patients had a poor outcome; three died and three had end-stage renal disease. Eight patients (group 2) were treated with repeated pulses of 1 gm of IVMP for four to 21 months. Six of the eight patients had a favorable outcome, with four in complete remission and two in partial remission. One of the eight patients had partial response with stable renal disease at 16 months after pulse therapy. Only one patient had no response, with gradual worsening of renal function. All patients in both groups had rapid improvement of levels of anti-DNA and CH50 after pulse therapy was started. Patients in group 2 were compared to 21 randomized patients (group 3) with comparable severity of disease. Renal function deteriorated in group 3, with a mean duration of disease of 82.5 +/- 56.4 months. Renal function improved in group 2, with a mean duration of disease of 87.8 +/- 46.8 months. We conclude that repeated monthly pulse therapy with IVMP in severe SLE was effective and that major side effects can be avoided with proper timing of pulsing.

Acute Disease↗