Biomedical subjects

S M Mates

Publications and source records attributed to S M Mates.

8 recordsLinked to original sources

PubMed1992

Granulomatous prostatitis due to Mycobacterium avium complex.

Granulomatous infections of the genitourinary tract are rare, especially those caused by nontuberculous mycobacteria. A case of prostatitis due to Mycobacterium avium complex in an immunocompetent man is reported. The patient had sterile pyuria, and a Mantoux skin test, using 5 tuberculin units, was positive (induration, 10 mm in diameter). Pathologic examination of the prostate revealed necrotizing granulomata with acid-fast bacilli, and repeated performance of urine cultures before initiating therapy yielded M. avium complex.

Aged↗

PubMed1988

Metastatic gestational choriocarcinoma: two cases.

Gestational choriocarcinoma is a rare, aggressive cancer of post-partum women. It metastasizes rapidly and can initially appear with involvement of the gastrointestinal, respiratory, genitourinary, or central nervous systems. Some reported cases show only metastatic foci with apparent spontaneous resolution of the primary site. We present two cases of gestational choriocarcinoma, showing some of these unusual presentations of a primarily gynecological problem.

Adolescent↗

PubMed1987

Technetium Tc 99m diphosphonate bone scan. False-normal findings in elderly patients with hematogenous vertebral osteomyelitis.

Hematogenous osteomyelitis is usually diagnosed by an abnormal technetium Tc 99m diphosphonate bone scan in symptomatic patients who have positive blood cultures. False-normal 99mTc bone scans have been described recently in neonates with biopsy-proved osteomyelitis. This phenomenon seems to be extremely rare in adults. Two elderly patients with hematogenous vertebral osteomyelitis had normal technetium Tc 99m diphosphonate bone scans when first evaluated. In both cases the bone scans became abnormal four to six weeks after onset of symptoms and two to four weeks after the initial normal results of the study. When suggested by the clinical picture, hematogenous osteomyelitis cannot be ruled out by a normal 99mTc bone scan at any age. Gallium scan, computed tomographic scan, or bone biopsy can be helpful in such cases.

Aged↗

PubMed1986

Compartment syndrome associated with Staphylococcus endotoxin.

A case is presented of a 23-year-old athletic male student who developed right knee pain after a weekend of strenuous activity. The patient failed to respond to conservative measures; pain increased and within 24 hours he developed fever, chills and swelling of the involved knee. On admission to the hospital, the patient appeared toxic. Efforts to establish a diagnosis, particularly with the use of computerized axial tomography are described. It was surgical decompression of muscular swelling of the distal thighs, revealed by CT scanning, that led to the diagnosis and the successful treatment that followed.

Adult↗

PubMed1985

Perceptual organization and apparent brightness in subjective contour figures.

According to a number of theories subjective contours arise from brightness contrast and/or assimilation. The apparent brightness gradients generated by these effects are assumed to give rise to the perception of contours delineating the gradients. A study is reported in which naive observers were shown a subjective contour display and asked to report what they saw. They were then asked to judge whether the center or the surround of the display appeared brighter. Subjects whose reports indicated that they had seen the subjective contour figure showed an overwhelming preference for the center of the display being brighter than the surround. However, subjects who did not see the subjective contour figure did not differ significantly in their selection of the center over the surround. This finding presents difficulties for any theory which derives subjective contours from the apparent brightness difference.

Color Perception↗

PubMed1985

Mediterranean spotted fever in an American woman.

Mediterranean spotted fever is common in southern Europe, the Middle East, and North Africa, but is unknown in the United States. It has a clinical picture resembling Rocky Mountain spotted fever, but it is a milder disease. We report a case of Mediterranean spotted fever in a young American woman returning from Morocco and review the clinical picture of this disease.

Adult↗

PubMed1983

Membrane potential in anaerobically growing Staphylococcus aureus and its relationship to gentamicin uptake.

The electrical potential (delta psi) across the cytoplasmic membranes of Staphylococcus aureus cells growing under aerobic and anaerobic conditions was determined by measuring the equilibrium distribution of [3H]tetraphenyl phosphonium. In conjunction, gentamicin uptake and killing were studied in the same cells under identical conditions. Under aerobic conditions, delta psi was -169 mV, gentamicin uptake was readily demonstrable, and the number of viable cells decreased by almost four orders of magnitude in the presence of antibiotic. In contrast, delta psi was -142 mV anaerobically, gentamicin uptake was essentially nonexistent, and the aminoglycoside had no effect on viability. Remarkably, when the ionophore nigericin was added under anaerobic conditions, delta psi increased to the level observed aerobically, gentamicin uptake tripled to about 18% of the aerobic level, and viability decreased by one order of magnitude. The results are consistent with other observations (Mates et al., Proc. Natl. Acad. Sci. U.S.A. 79:6693-6697, 1982), indicating that the relationship between delta psi and gentamicin uptake is gated, and suggest that diminution of delta psi may be an important factor in aminoglycoside resistance under anaerobic conditions.

Anaerobiosis↗

PubMed1982

Membrane potential and gentamicin uptake in Staphylococcus aureus.

At pH 5.0, the electrical potential (delta psi, interior negative) across the plasma membrane of Staphylococcus aureus exhibits a minimum of -85 to -90 mV; the pH gradient (delta pH, interior alkaline) across the membrane approximates a maximum of about -100 mV. Under these conditions, uptake of the aminoglycoside gentamicin is negligible, and viability of the organism is not impaired by the antibiotic. In contrast, at pH 7.5, at which delta psi is about -130 mV and delta pH is 0, gentamicin uptake is observed and the drug markedly decreases viability. Dramatically, when the ionophore nigericin is added at pH 5.0, gentamicin uptake is induced, there is a striking decrease in viability, and the effect is associated with an increase in delta psi at the expense of delta pH. Consistently, valinomycin, which dissipates delta psi in the presence of potassium, abolishes gentamicin uptake and killing. In addition, from pH 5.0 to pH 7.5, there is a direct relationship between the magnitude of delta psi and both gentamicin uptake and its bactericidal effect. However, a threshold delta psi of -75 to -90 mV is apparently necessary to initiate uptake and killing. These observations provide a strong indication that delta psi plays a critical role in the uptake and antibacterial action of gentamicin and suggest that nigericin-like ionophores may be clinically useful in synergy with aminoglycosides.

Biological Transport, Active↗