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Biomedical subjects

M I Cohen

Publications and source records attributed to M I Cohen.

At least 73 records · Page 4Linked to original sources
PubMed1984

Discharge properties of dorsal medullary inspiratory neurons: relation to pulmonary afferent and phrenic efferent discharge.

In decerebrate paralyzed cats ventilated with a cycle-triggered pump system that delivered inflation during the central inspiratory (I) phase (indicated by efferent phrenic discharge), activity of 90 neurons with inspiratory-modulated discharge was recorded in the region of the ventrolateral nucleus of tractus solitarius (vlNTS) in the medulla. Of these, 82 had centrally originating I patterns (69 augmenting, 13 decrementing), and 8 were "pump" neurons. The neurons were classified into functional types by the application of inflation tests, the main test being withholding of the inflation usually delivered during the central I phase. This maneuver eliminated phasic pulmonary afferent input and produced lengthening of the I phase. The neurons' responses were heterogeneous, and were classified as: excitation by inflation (inflation(+], no significant effect of inflation (inflation(0], and depression by inflation (inflation(-]. Application of inflation during the expiratory (E) phase only rarely produced excitation of central I neurons. The I neurons excited by inflation correspond to the "I-beta" neurons of earlier studies. On the basis of the multimodal distribution of their discharge onset times relative to phrenic onset, they were classified as early onset or late onset. In contrast, the inflation(0) and inflation(-) neurons, which correspond to the "I-alpha" neurons, almost exclusively had early onsets. The pump neurons could be distinguished from the inflation(+) I neurons by the effects of inflations delivered during E: the former were equally excited by inflations during E and during I, while the latter were not excited or were minimally excited by inflation during E. Thus, the pump neurons had lung afferent inputs but no inputs from the central I pattern generator, while the inflation(+) I neurons had both kinds of input. The neurons having decrementing discharge during I (early inspiratory and expiratory-inspiratory) were depressed by inflation. Cross-correlation histograms (CCH) of unit firing versus whole phrenic (contralateral and ipsilateral) activity on a short time scale (milliseconds) were computed; the majority of these had high-frequency oscillations, with mean period of 14.6 +/- 3.6 (SD) ms. The CCHs for the different groups of neurons were analyzed with respect to a) strength of correlation as a function of laterality and b) lag of the main correlation peak. Both the inflation(0) and inflation(+) neuronal groups had correlation properties suggesting that these neurons monosynaptically excite phrenic motoneurons.(ABSTRACT TRUNCATED AT 400 WORDS)

Afferent Pathways↗
PubMed1983

Inhibitory effects on fast sympathetic rhythms.

In decerebrate cats, the effects of barbiturate anesthesia and of pulmonary afferent activity (produced by lung inflation) on fast (ca. 10/s) rhythms in sympathetic efferent discharges (cervical sympathetic and splanchnic) were analyzed. These inhibitory influences, in addition to reducing overall activity, eliminated or drastically reduced the highest frequency oscillations. Barbiturate anesthesia also markedly reduced high frequency oscillations (ca. 100/s) in phrenic discharge. Apparently, then, the occurrence of fast neural rhythms is dependent on the level of tonic excitatory activity.

Animals↗
PubMed1982

Self-detection of a breast mass in adolescent females.

The frequency of self-discovered breast masses in adolescent females has not previously been described. The histologic diagnosis rather than the means of detection has been the focus of previous surveys. Seven characteristics of 95 patients admitted from 1968-1979 for the evaluation of a breast mass were delineated. The mean age at hospitalization was 15.9 years (range 12-20). The delay from detection to hospitalization was 7.2 months (range 0.5-72). In 77 cases the mass was detected by the patient; 11 were found during a physician examination, 4 by a family member, and 3 by an unrecorded source. Diagnoses were fibroadenoma (71), abscess (11), cyst (9), lipoma (2), and cystosarcoma phyllodes (2). The median length of the masses was 2.6 cm, width 2.3 cm, with a median mass area (diameter x length) of 6 cm2. When patients were compared for age, delay in hospitalization, means of detection, family history, and mass size, the girls with abscesses were younger and had a shorter time delay before hospitalization. Self-discovery was the means of detection in 77 of 95 (81%). The means of detection is an important factor to consider in weighing the merits of teaching breast self-examination procedures to adolescent females.

Abscess↗
PubMed1981

Influence of familial hypertension on blood pressure during adolescence.

The relationships of familial hypertension and height, weight, and blood pressure (BP) were studied in two adolescent populations. Subjects having hypertensive first-degree relatives were matched to control subjects without such a family history. The group with familial hypertension demonstrated a slightly higher average BP but also had a greater mean body weight and ponderal index than the control group. After controlling for weight, male but not female subjects with a family history of hypertension had a greater prevalence of elevated BP and higher average pressures than controls. The factors of above-average weight and familial hypertension appear to interact so as to produce an excessive prevalence of elevated BP. These trends suggest that teenagers with hypertensive first-degree relatives constitute a special risk group that should be closely monitored.

Adolescent↗
PubMed1981

Sympathetic rhythms in spinal cats.

Simultaneous recordings from preganglionic sympathetic nerves at different spinal levels, cervical sympathetic and greater splanchnic, reveal the presence of common periodicities as shown by cross-correlation and power spectral analysis; the major types of periodicities are cardiac, respiratory and 10/sec rhythm. These common periodicities could be explained in two ways: (1) there are common periodic inputs to the two types of preganglionic neurons; and (2) there are feedback connections in the spinal cord between the two groups of neurons. To distinguish between these two possibilities, spinal cord transections at C2-C3 were performed on decerebrate unanesthetized cats; recordings were then taken at hourly intervals for more than 12 h, during which time activity gradually increased but still remained small compared to pre-section levels. This low level activity showed no sign of periodicity. Asphyxia of sufficient duration produced increased activity in sympathetic nerves. Splanchnic activity during asphyxia had 2-3/sec oscillations; but the cross-correlation histograms (CCHs) of cervical sympathetic and splanchnic activity were almost flat. Strychnine excited spinal cord neurons more effectively than asphyxia; the CCHs showed locking of activity in phrenic, cervical sympathetic and splanchnic nerves on a slow time-scale (1-5 sec), but no appreciable locking of cervical sympathetic and splanchnic activity on a faster time-scale (100-500 msec) such as occurs in the intact animal. Thus, while there can be oscillation of sympathetic activity at the spinal cord level, the normally occurring synchrony of oscillations between different segmental levels is dependent on inputs from the brain stem.

Animals↗
PubMed1981

Recent separation and the onset of peptic ulcer disease in older children and adolescents.

The onset of peptic ulcer disease in adolescents often appears to be preceded by a separation or loss. We attempted to review data on, or to recontact, the 59 adolescent and preadolescent patients with peptic ulcer disease (gastric ulcer, duodenal ulcer, and hematemesis of unknown etiology) admitted to Montefiore Hospital and Medical Center between 1968 and 1979. We were able to obtain adequate retrospective data for 24 of these patients. Ten (42%) had encountered a separation or loss within 12 months of the onset of their illness. In 6 patients the event occurred within 4 weeks of admission. In a matched group of 24 appendectomy patients, 1 separation occurred in the 12 months prior to admission (mean 2 = 9.6; p less than 0.01). We conclude that in an adolescent population, a recent separation or loss may be associated with the onset of peptic ulcer disease in predisposed persons.

Adolescent↗
PubMed1981

Pulmonary afferent and central influences on respiratory phase-switching in the cat.

A striking feature of the mammalian respiratory rhythm generator is the abruptness of the transitions between the inspiratory (I) and expiratory (E) phases ("phase-switching"). Although reciprocal inhibitory actions between I and E neurons are important for maintaining the alternation of respiratory phases, phase-switching actions are probably produced by recurrent inhibitory neuronal loops acting within each phase. The operation of such negative feedback circuits has been studied using two types of experimental input: (a) activation of pulmonary stretch receptors by lung inflation, which shortens the I phase and prolongs the E phase, and (b) electrical stimulation in the rostral pontine "pneumotaxic center" region, which can produce premature I leads to E or E leads to I switching, depending on stimulation site. These inputs produce diverse effects on discharges of various types of medullary respiratory neuron; analysis of such observations has led to hypotheses about the possible roles of different neuron populations in phase-switching.

Afferent Pathways↗
PubMed1981

How is respiratory rhythm generated?

The time course of respiratory activity, e.g., the the abrupt transitions between the inspiratory (1) and expiratory (E) phases, can be explained by several types of interaction between brainstem respiratory neurons. 1) Reciprocal inhibition: Inhibition of E neurons by I neurons, and of I neurons by E neurons, has been demonstrated, a mechanism that prevents occurrence of activity in one set of populations during the period of activity of another set of populations. 2) Recurrent inhibition: During each respiratory phase, activity in recurrent loops gradually rises to levels sufficient to inhibit ongoing activity and produce abrupt phase-switching. a) I leads to E phase-switching: By use of lung inflation tests, several categories of I neurons in the region of the ventrolateral nucleus of tractus solitarius (NTS) have been specified; in particular, a population of late-I neurons has been found that may function to terminate the I phase. b) E leads to I phase-switching: Several populations of medullary neurons (early-E, late-E, and EI) have been found with responses to lung inflation that suggest that they may play a role in determining E phase duration and E leads to I switching; in particular, a population of early-E neurons in the NTS has been found whose discharge properties suggest that they may function to delay the onset of the succeeding I phase. 3) Recurrent excitation: There is evidence for the existence of recurrent excitatory actions among I neurons that may produce the augmenting pattern of I neurons' discharges.

Animals↗
PubMed1981

The adolescent with chronic disease.

The many challenging, painful and complex problems of chronic illness are intensified during the adolescent years due to a myriad of rapid growth and development changes which must occur in order to achieve complete maturity. The more traditional approaches to chronic illness predicated on the categorial disease or an organ system model have not been helpful in dealing with adolescents. Thus, a development approach is offered as a more appropriate methodology for addressing this complex problem. With increasing awareness of this development perspective and maximal use of medical, psychological and social technology and resources, chronically ill adolescents can in most instances be helped to lead satisfying and useful lives.

Adolescent↗
PubMed1980

Clinical pharmacology and adolescence.

When determining the type and timing of drug therapy for adolescents, certain biological and psychosocial factors unique to this age group must be considered. Modern drug monitoring techniques allow the physician to more successfully treat the adolescent patient.

Adolescent↗
PubMed1980

Importance, implementation, and impact of the adolescent medicine components of the Report of the Task Force on Pediatric Education.

The recently published Report of the Task Force on Pediatric Education has had a substantial impact on the growth of the field of adolescent medicine in three areas. First, the report continually emphasized the special needs for improved health services for teenagers and the training of their physicians. Secondly, it intentionally did not suggest a specific method by which to render care or offer training in adolescent medicine. Thus, a wide array of individualized services and training options became immediately available. Finally, the report has had a significant influence on a variety of organizations, in both the private and public sectors. New monies, legislation, and approaches to the delivery of adolescent health care and for those in training to provide that care therefore emerged as a direct consequence of the report.

Adolescent↗
PubMed1980

Special considerations in pregnancy prevention for the mentally subnormal adolescent female.

Eight retarded teenage girls are presented whose cases highlight some of the considerations in pregnancy prevention for this population. Their mean age was 15.8 years, and 7 were considered to be educable (IQ 50-70) and 1 of borderline intelligence. Presenting complaints included pregnancy, sexual molestation, salpingitis, and a request for contraception in 2 patients each. Pelvic examination with no anesthesia was accomplished after multiple educational sessions in 7 patients. Contraceptive choices included an intrauterine device (2 patients), postcoital estrogen (1 patient), abstinence (1 patient), no contraception (2 patients). Of the 2 pregnant teenagers, 1 elected to continue and 1 to terminate. Unique considerations were the need for current information about consent, alternatives to sterilization, specific risks of contraception for the retarded with medical problems, and communication skills for eliciting sexual information and attitudes. The 8 patients presented reflect the special features posed by the interaction of adolescence, sexuality, and retardation.

Adolescent↗
PubMed1980

Laparoscopy for presumed nonacute salpingitis: a new look at an old problem.

The increased prevalence of venereal disease among adolescents has resulted in a rise in nonacute salpingitis. Laparoscopy was evaluated as an aid in the diagnosis and treatment of presumed nonacute salpingitis in 29 adolescents. The patients had a mean duration of symptoms of 5.5 months, 50% had a recent history of discharge and/or bilateral pelvic pain, and on examination 50% had pain on motion of the cervix, 75% had adnexal tenderness, and 50% had a palpable adnexal fullness or mass. Anatomic findings at laparoscopy included normal pelvic structures in 8, active salpingitis in 13 and nonacute disease in 8. The anaerobic, aerobic, and viral peritoneal cultures obtained at laparascopy from 22 patients resulted in no growth in 18. The four with positive cultures had one organism identified in three cases and two organisms in one case. Anatomic findings were more helpful in diagnosis than the bacteriologic analysis, and our results suggest that laparoscopy increases diagnostic accuracy in the management of presumed nonacute salpingitis.

Adolescent↗
PubMed1980

The effect of phototherapy on intestinal mucosal enzyme activity in the Gunn rat.

Infants undergoing phototherapy may develop loose stools. Acquired lactase deficiency secondary to this treatment modality was suggested as a cause for the diarrhea. The effects of light energy directly on intestinal enzymes and indirectly through bilirubin photooxidation products were studied. Adult homozygote and heterozygote Gunn rats were treated with light for varying periods while littermate controls were kept in the dark. Intestinal lactase, sucrase and GGTP activities and serum bilirubin concentrations were determined. Jaundiced and non-jaundiced 1-week-old suckling Gunn rats were treated with light for 96 h, and intestinal lactase activity determined. No decreases in lactase, sucrase or GGTP activities were observed suggesting the reported diarrheal states following phototherapy are not related to light energy or photooxidation products.

Animals↗