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Biomedical subjects

M Cohen

Publications and source records attributed to M Cohen.

At least 541 records · Page 30Linked to original sources
PubMed1992

Patient positioning for the operative approach to midline intracerebral lesions: technical note.

Patients undergoing craniotomies for intracerebral lesions are generally positioned in such a way that the lesion is highest in the field. For midline lesions alongside the falx, patients are commonly positioned on their backs for an anatomically symmetrical approach. We propose positioning the patient in the lateral decubitus position ipsilateral to the lesion to take advantage of gravity by allowing the brain to fall away from the midline, thus obviating the need for retraction. We have used this position in 15 cases of falcine and parafalcine tumors to great advantage, without encountering untoward operative or anesthetic complications.

Craniotomy↗
PubMed1992

Calcium and phosphorus content of roots exposed to the oral environment.

This study analyzed the calcium and phosphorus content of extracted tooth roots exposed to the in vivo oral environment. 20 teeth were obtained from 16 patients and divided into two groups of 10 teeth each. In group 1, the teeth had gingival probing depths of 5 mm or more, and teeth of group 2 had gingival recessions of 3 mm or more. Prior to extraction, the gingival margin location was recorded by placing a groove on the tooth surface. After extraction, the teeth were sectioned coronal-apically, air dried and coated with carbon. Energy dispersive X-ray spectra, excited in a scanning electron microscope, were analyzed to measure relative calcium and phosphorus contents and for calculation of their ratios. X-rays were collected from two positions on the sectioned root. Experimental positions were selected within the exposed portion of the roots of groups 1 and 2, and unexposed positions were selected from that portion of the same root with attached periodontal membrane. At each position, calcium and phosphorus content was measured at 4 depths into the root surface: in cementum, in dentin three-quarters of the distance to the pulp chamber, and at 2 locations in between on either side of the cemento-dentinal junction. Analysis of data demonstrated large variations in calcium and phosphorus content from surface to surface of individual teeth and from tooth to tooth in a subject. No statistically significant differences were found between experimental and unexposed locations. Calcium and phosphorus contents were greater in roots exposed to pockets when compared to roots exposed by recession at both experimental and unexposed locations.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Temporally related changes of sleep complaints in traumatic brain injured patients.

Sleep complaints were obtained from 22 hospitalised patients with traumatic brain injury of recent onset (median 3.5 months after injury) and were compared with those of 77 discharged patients who had sustained brain injury about two to three years (median 29.5 months) previously. A high incidence of sleep complaints was noted in both groups (72.7% and 51.9% respectively). Disorders in initiating and maintaining sleep (DIMS) were the most common complaints among hospitalised patients (81.2%), whereas disorders of excessive somnolence (DOES) were common in discharged patients (72.5%). This difference in the nature of the complaints was apparently due to differences between the two groups in the time elapsed since injury, duration of coma, and immediate environmental conditions. In discharged patients with sleep complaints, neurobehavioural impairments and a poorer occupational outcome were more common than in those discharged patients without sleep complaints. It is suggested that early evaluation and treatment of sleep disturbances must be considered an integral part of the rehabilitation process.

Adult↗
PubMed1992

The efficacy of a peptide-nucleic acid solution (Reticulose) for the treatment of hepatitis A and hepatitis B--a preliminary controlled human clinical trial.

To complete this preliminary study 53 patients were chosen. All patients were screened, diagnosed for Hepatitis A or Hepatitis B and separated into treatment and control groups. All of the patients selected were in the early onset stage of their infection, and diagnosed for Hepatitis A or B by appropriate laboratory tests with special attention to Anti-HAV, IGM and HepB surface Antigen to carefully differentiate those with A from those with B. The treated patients received Reticulose for a 15 day period and the control patients received placebo injections of physiological saline. Reticulose patients with Hepatitis showed positive. 18 patients with Hepatitis B and 9 patients with Hepatitis A were treated with Reticulose, compared to 17 control patients with Hepatitis B and 9 control patients with Hepatitis A treated with placebo. Based upon laboratory findings of several parameters; Prothrombin times, Serum bilirubin, white blood cell (WBC count) and clinical observations; Reticulose treated patients appeared to show significant improvement. The bilirubin levels of 83% of patients with Hepatitis B, treated with Reticulose for 15 days were in normal range in 30 days. None of the control patients were within normal range after 30 days with placebo treatment. Of Hepatitis A patients treated with Reticulose, 100% showed normal bilirubin after 30 days. Of control patients with Hepatitis A, only 22% were in normal range after 30 days. The findings in this preliminary trial lead to the conclusion that Reticulose appears to significantly reduce the recovery time and return to normal for patients with an acute episode of Hepatitis A or B. Further study is indicated.

Adolescent↗
PubMed1992

Melatonin and melatonin-progestin combinations alter pituitary-ovarian function in women and can inhibit ovulation.

Although melatonin (MEL) controls seasonal reproductive cyclicity in some mammalian species, its role in women is controversial. In this study data are presented related to the influence of MEL or MEL-progestin combinations on the pituitary-ovarian axis and ovulation in 32 women. MEL was administered in a dosage of 300 mg to 12 women for 4 months [to 8 women daily (days 1-30) and to 4 women on days 5-17 of the cycle]. MEL was also combined with the synthetic progestin norethisterone (NET) in an attempt to evaluate MEL's effect on a partially suppressed pituitary-ovarian axis. In 16 women, 4 combinations were tested on 4 women each on days 1-21: dosages of 300 mg MEL/0.75 mg NET, 75 mg MEL/0.75 mg NET, 7.5 mg MEL/0.75 mg NET, and 75 mg MEL/0.30 mg NET. In addition, 2 women were medicated with 300 mg MEL alone, and 2 were medicated with 300 mg MEL/0.15 mg NET on days 1-21 for 2 months. During the study, LH, FSH, estradiol (E2), and progesterone (P4) blood levels were determined at regular intervals. After a period of 4 months, daily administration of 300 mg MEL (days 1-30) caused significantly decreased mean LH levels compared to those in 8 nonmedicated controls (P less than 0.001). Also compared to nonmedicated control data, a significant inhibition of P4 in the first and fourth medication months (P less than 0.001) was observed. LH and E2 inhibition reached significance in the fourth medication month (P less than 0.005). Also, the treatments of 300 mg MEL (days 5-17) and 75 mg MEL combined with 0.3 mg NET caused a significant decrease in LH, E2, and P4 levels compared to those in the nonmedicated control group in the first and fourth medication months (P less than 0.05). The data further suggest an additive or synergistic effect between MEL and NET. The medications did not alter sleep-wake rhythms and were not complicated by any side-effects. The presented data suggest that MEL and MEL/NET combinations inhibit ovarian function in women, and that MEL/NET combinations can emerge as effective oral contraceptives.

Adult↗
PubMed1992

Amyloidoma of the CNS. I. Clinical and pathologic study.

We report a 32-year-old man with a 4-year history of headaches, seizures, and dementia secondary to multifocal amyloidomas in the white matter. Immunohistochemical and electron microscopic analyses suggest that the amyloidomas resulted from processing of plasma-cell-derived amyloidogenic protein by microglial cells.

Adult↗
PubMed1992

Amyloidoma of the CNS. II. Immunohistochemical and biochemical study.

We present the immunohistochemical and biochemical identification of an amyloidoma localized to the cerebral white matter in a patient who shows no evidence of systemic or extracranial localized amyloid deposits. Immunohistologic and immunochemical studies, using antibodies against biochemically different amyloid fibrils and amyloid-associated proteins, showed reactivity with antibodies only to lambda light chain and serum amyloid P-component. Amino acid sequence analysis of the purified amyloid fibrils extracted from the brain tumor indicates that the amyloid protein is an unusual immunoglobulin lambda light chain, starting at residue five of the variable domain. These fibrils consist of lambda chain fragments of different lengths (10 to 30 kd) very likely arising by polymerization of the amyloid subunit or sequential proteolytic cleavage of the light chain, or both. After exposure to denaturing agents, the 10-kd subunit retains the characteristics of native amyloid fibrils by electron microscopy.

Adult↗
PubMed1992

A prospective study of community-acquired pneumonia in Hong Kong.

A prospective study of community-acquired pneumonia in Hong Kong was carried out between January and December, 1988. Ninety adults (57 male) with a mean age of 57.3 years were admitted to the Prince of Wales Hospital with community-acquired pneumonia. The etiologic diagnosis of pneumonia was made in 37 cases (41 percent). Pneumococcal infection was diagnosed in 11 patients (12 percent). The same number of patients had pulmonary tuberculosis presenting as acute pneumonia. It could not be differentiated from other causes of pneumonia on clinical and radiologic grounds, although pleural effusion and upper lobe involvement were more common in patients with tuberculosis. Chlamydia species were identified in five patients (6 percent) and Mycoplasma pneumoniae was identified in three patients (3 percent). There was no case of Legionnaires' disease. The etiologic agent could not be identified in 59 percent of cases. The low incidence of etiologic diagnosis of community-acquired pneumonia was probably related to the widespread use of antibiotics in private practice. Tuberculosis is an important cause of community-acquired pneumonia in Hong Kong and this diagnosis should be considered in patients who fail to respond to first-line antibiotics.

Adult↗
PubMed1992

Defining the relationship between cochlear hearing loss and acoustic reflex thresholds.

In this study several methods of defining the relationship between the magnitude of cochlear hearing loss and the acoustic reflex threshold (ART) levels were examined, with a view to defining the appropriate upper limits of ART that would ease clinical applicability and reduce the false positive rate. The 90th percentile, two standard deviations (SD) from the mean, the regression method and an empirical method based on the scatter plots of the ART at each activator frequency were all applied to the results of 99 patients with cochlear and/or peripheral vestibular pathology. The upper limits of ART defined on the basis of the scatter plots provided the most appropriate upper limits for different ranges of hearing loss, with relatively few false positives. A clinical criterion based on the ART levels at adjacent frequencies is proposed, which further reduces the false positive rate and could also prove effective in the differential diagnosis of cochlear from retro-cochlear lesions.

Acoustic Impedance Tests↗
PubMed1992

The retroauricular coronal incision.

The coronal incision has been modified so that if it needs to be extended to improve exposure, the extension will be behind the ear and therefore less noticeable. The incision has been used in 25 adults and 30 children with no complications. Its cosmetic appearance is superior to the preauricular coronal incision, and it is preferred especially by young people in whom the scar tends to widen with time.

Adult↗
PubMed1992

Cell-mediated immunity to orbital tissue antigens in thyroid-associated ophthalmopathy determined using the leukocyte procoagulant activity assay.

While it is generally accepted that thyroid-associated ophthalmopathy (TAO), a progressive inflammatory disorder of the extraocular muscle and orbital connective tissue (OCT), is immunologically mediated the nature of the underlying abnormalities is poorly understood. Although there is considerable evidence for antibody-mediated immunity against both eye muscle (EM) and OCT antigens in TAO a role of cell-mediated immunity (CMI) has not been studied in detail. We have used a new sensitive test for CMI, the leukocyte procoagulant activity (LPCA) assay and tested blood leukocytes from patients with TAO and autoimmune thyroid disease (ATD) without evident ophthalmopathy for reactivity against pig eye muscle (PEM) and human thyroid and OCT membrane and soluble fractions. In some cases human EM fractions were also tested. Preparations of PEM membrane (PEMM) and human thyroid membrane induced a significant LPCA response in both groups of patients. PEM cytosol, human OCT membrane and cytosol and human spleen membrane did not evoke a significant response in either group of patients. There were significant positive correlations in patients with TAO between (i) LPCA in response to PEMM and that to human thyroid membrane and (ii) LPCA in response to human thyroid membrane and that to human EM membrane. In patients with TAO there were no significant associations between LPCA response to PEMM and the detection of serum antibodies to a 64 kDa EM membrane protein in immunoblotting, or between LPCA response to PEMM and the duration or severity of the ophthalmopathy or clinical evidence for eye muscle involvement. These findings confirm a role of cell-mediated immunity against eye muscle antigens in thyroid-associated ophthalmopathy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Splendid spaces.

Welcome to FM's third gallery exhibit of visually impressive & beautifully functional noncommercial foodservice design projects. The five new & renovated facilities on display are among the most interesting recent designs formulated to solve operational problems such as congested flow, restricted space and poor lighting. Wander through the gallery & observe how careful planning & architectural ingenuity have been arranged to create striking compositions of splendid space.

Efficiency↗
PubMed1992

[Current role of laparoscopy in the diagnosis and treatment of ovarian cysts].

Between October 1986 and March 1990, 220 patients underwent surgical treatment for ovarian cysts. 156 of these patients underwent an initial celioscopy and could potentially benefit from celiosciopic treatment. The group mean age was 33.3 years. The circumstances under which the cysts were discovered usually consisted of pelvic pain or diagnosis during a routine examination. Twenty-four patients underwent laparotomy immediately after coelioscopy either due to a suspect macroscopic diagnosis either due to technical difficulties. 84.6 percent of the patients in the group were able to undergo celioscopic treatment only, essentially consisting of intraperitoneal cystectomy. The main advantages were the reduction in adherent sequelae in these women of a sexually active age, but also some financial savings related to the reduced duration of hospitalization and of sick leave. The theoretical reservations consist of the risk of malignancy and macroscopic diagnosis following coelioscopic exploration must be very restricted, with laparotomy whenever there is any doubt. No malignant tumor was escaped detection in this group.

Adult↗
PubMed1992

Early, aggressive management of postoperative oropharyngocutaneous fistulas.

Oropharyngocutaneous fistulas remain a serious and potentially lethal complication. Advantages from surgical repair and the use of musculocutaneous flaps have been demonstrated. Timing of the procedure, however, has not been adequately addressed or emphasized. This report presents our experience with early, aggressive management of postoperative orocutaneous fistulas. Patients were reoperated at an average of 12 days after the initial surgery and underwent exploration, debridement of all devitalized tissues, and closure by reelevation of previously used flaps or with additional flaps. All wounds healed without further problem. We conclude that as long as the patient's general condition permits, early, aggressive management of fistulas should be the procedure of choice to reduce hospital stay and costly wound care and to avoid maceration and partial or complete necrosis of flaps and the potential rupture of the carotid artery. Timely radiotherapy can then be delivered, and quality of life can be significantly improved.

Female↗
PubMed1991

Clinical and angiographic characteristics and outcome of patients with rest-unstable angina occurring during regular aspirin use.

Today many patients admitted with an acute coronary syndrome are already taking aspirin. Because they have symptoms despite antithrombotic therapy, these patients are presumed to be at higher risk for subsequent clinical events. In a pilot trial of antithrombotic therapy in patients with unstable angina at rest or non-Q wave infarction, 93 patients admitted within 48 h of pain were prospectively followed up for 12 weeks. On admission, 29 patients (31%) were already taking daily aspirin; 64 (68%) were receiving no antiplatelet agent. After enrollment all patients received antithrombotic therapy with either aspirin or heparin according to protocol regardless of prior aspirin use. The two groups (prior users versus nonusers of aspirin) were similar with regard to age, gender, coronary risk factors, prior antianginal medication, duration of symptomatic coronary disease, presentation with non-Q wave infarction and extent of electrocardiographic changes on admission. Quantitative analysis of coronary arteriograms (on a 0 to 10 scale) showed similar myocardium-in-jeopardy scores (JS). Follow-up events (recurrent ischemia [Isch], infarction [MI] and revascularization [Revasc]) were: (formula: see text) Aspirin users experiencing rest angina are similar to other patients with ischemic rest pain. The "resistant to aspirin" group does not constitute a subgroup that is at higher risk for cardiac events or revascularization.

Adult↗
PubMed1991

Anticholinergic drugs potentiate dopamine D1 but not D2 antagonists on a conditioned avoidance task in rats.

The present study investigated whether blockade of conditioned avoidance responding (CAR) in rats by selective D1 and D2 receptor antagonists could be differentially affected by anticholinergics. The results show that atropine and scopolamine dose-relatedly antagonized the effects on CAR of two specific D2 receptor blockers, haloperidol and raclopride, but potentiated the effects of three specific D1 receptor antagonists, SCH 23390, SCH 39166 and NO-01-0756. Of the less specific dopamine receptor antagonists tested, scopolamine blocked the effects of clozapine and cis-flupenthixol, but did not alter the effects of chlorpromazine, thioridazine or cis-piflutixol. Although the mechanisms involved in the differential shifts by the anticholinergics are unknown, the results are consistent with the view that CAR antagonism by the specific D2 vs. D1 receptor antagonists involves unique and separate mechanisms of action. With respect to the less specific dopamine receptor antagonists, the CAR blockade seen with clozapine and cis-flupenthixol might reflect predominant D2 receptor blockade because their effects were blocked by atropine. In contrast, the CAR blockade by chlorpromazine, thioridazine and cis-piflutixol antagonists might be mediated by equal degrees of D1 and D2 receptor blockade inasmuch as they were not blocked or potentiated by atropine. The antagonism of CAR in rats by the D1 receptor antagonists suggests that these drugs have potential antipsychotic activity in humans. However, they do not appear to enhance central cholinergic transmission and therefore may be devoid of the side effects produced by the antipsychotics in clinical use.

Administration, Oral↗