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Biomedical subjects

J A Matochik

Publications and source records attributed to J A Matochik.

At least 37 records · Page 2Linked to original sources
PubMed1995

Regional cerebral glucose metabolism in autopsy-confirmed Creutzfeldt-Jakob disease.

Regional cerebral glucose metabolism was measured in a 72-year-old man, with Creutzfeldt-Jakob disease (CJD), by positron emission tomography using [18F]-2-fluoro-2-deoxy-D-glucose as the tracer. The diagnosis of CJD, a rare neurodegenerative disorder, was confirmed at autopsy 13 months later. Compared with five unaffected elderly men, the patient had reduced metabolism heterogeneously distributed throughout the brain. The hypometabolism was most evident in the right hemisphere, particularly in the posterior frontal, parietal, Sylvian, and temporal regions. This left-right asymmetry is more extensive than that previously reported in Alzheimer's disease, and may provide a useful metabolic marker for early diagnosis of CJD.

Aged↗
PubMed1994

Intracranial androgenic activation of male-typical behaviors in house mice: motivation versus performance.

Castrated male mice were bilaterally implanted with 27 ga cannulae containing testosterone into either the septum, medial preoptic area (MPO), or corticomedial amygdala. One additional group of castrates received no hormone and another received only systemic testosterone via subcutaneous silastic capsules. All males were subsequently tested for ultrasonic mating vocalizations, urine marking, mounting behavior, aggression and gender preference, all of which are androgen-dependent, male-typical behaviors. In general castrates receiving no hormone performed these behaviors at low levels and animals receiving systemic testosterone performed the behaviors at normal male-typical levels. Ultrasonic vocalizations in response to female urine were activated by MPO implants. Urine marking in response to female urine appeared to be partially activated only with MPO implants. Very little mounting or fighting were seen in the brain implanted groups. Gender preference (for females over males) was restored with MPO implants and appeared to be partially activated with septal implants. The seminal vesicles of the castrates receiving brain implants were not significantly different from those receiving no hormone indicating that little or no implanted hormone was exiting the brain into general circulation. The implications of these findings for the neuroanatomy of sexual motivation and performance are discussed.

Aggression↗
PubMed1994

Dissociation of androgen-dependent sociosexual behaviors in response to castration in Long-Evans rats.

Copulatory behavior and associated social behaviors such as ultrasonic vocalizations and scent marking are reduced in frequency following castration and are restored by exogenous administration of androgens. In the present study, we report the behavior of a subgroup of male Long-Evans rats in which there was a dissociation between the responses of androgen-dependent behaviors to castration. Five weeks after castration, 52% of the males tested (13 of 25) had higher 50 kHz vocalization frequencies than during precastration tests. This group continued to emit vocalizations after castration and actually increased their number of vocalizations over postcastration tests (pretest: 34.5 +/- 4.8 to week 15: 62.8 +/- 10.9/10 min test). The remaining males (n = 12) exhibited a decline in vocalizations (pretest: 29.7 +/- 5.1 to week 15: 6.5 +/- 2.7) that we typically observe in our laboratory. Both groups showed the expected decline in scent-marking frequency over the postcastration tests and were impaired in performance of copulatory behavior. Seminal vesicle and adrenal gland weights did not differ between the two groups. The 25 males were of the same genetic strain as previous animals in our laboratory except that they were born and raised in a different location prior to shipment to our laboratory. Androgens, therefore, may be only one of the possible influences mediating ultrasonic vocalizations.

Androgens↗
PubMed1994

A double FDG/PET study of the effects of scopolamine in older adults.

Two consecutive positron emission scans were done in one session using a double injection method of [18F]2-fluoro-2-deoxyglucose administration to examine the effects of the antimuscarinic drug scopolamine on cerebral glucose metabolism in ten older adults. Scopolamine causes temporary memory impairment, and its effects have been used to model aspects of the cognitive impairment that occur in Alzheimer's disease (AD). Cortical metabolic rates of patients with AD have been reported to be depressed, especially in parietal, temporal, and frontal association areas. After scopolamine administration to the elderly volunteers, absolute and normalized glucose metabolic rates were depressed in prefrontal and occipital regions and increased in parietal-occipital cortical regions and a left middle temporal region. These changes in the older volunteers are generally not consistent with changes seen in AD. We conclude that deficits in muscarinic system function may contribute to some but not all of the hypometabolic changes seen in AD patients.

Brain↗
PubMed1994

Cerebral glucose metabolism in adults with attention deficit hyperactivity disorder after chronic stimulant treatment.

OBJECTIVE: The authors examined the effects of chronic stimulant treatment on cerebral glucose metabolism in adults diagnosed with attention deficit hyperactivity disorder (ADHD), who were studied by means of positron emission tomography (PET) with [18F]fluorodeoxyglucose as the tracer. METHOD: Each subject received two PET scans, the first before drug treatment and the second after treatment with daily oral doses, individually titrated for clinical effect, of either methylphenidate (N = 19) or d-amphetamine (N = 18) for a minimum of 6 weeks. The subjects completed behavioral self-report measures before and at the end of the medication period. RESULTS: Neither stimulant medication changed global, or whole-brain, metabolism, although both drugs increased systolic blood pressure. Metabolism in only two of the 60 brain regions sampled was changed by methylphenidate, while d-amphetamine exhibited no effect on regional metabolism. Both drugs were associated with significant improvement in behavior, as evidenced by improved ratings for restlessness and ability to maintain attention. CONCLUSIONS: While the present study does not demonstrate any robust metabolic effects of chronic stimulant treatment, the behavioral data strongly indicate that methylphenidate and d-amphetamine are effective agents for the treatment of adults with ADHD.

Adolescent↗
PubMed1994

Effects of intravenous dextroamphetamine on brain metabolism in adults with attention-deficit hyperactivity disorder (ADHD). Preliminary findings.

The effects on brain metabolism of the intravenous (i.v.) administration of dextroamphetamine was assessed by positron emission tomography (PET) with [18F]-fluorodeoxyglucose (18-FDG) in 8 adults with attention-deficit hyperactivity disorder (ADHD). During the 3-hour 18-FDG PET session, each adult underwent the initial scan following i.v. infusion of placebo and a second scan following i.v. infusion of 0.15 mg/kg dextroamphetamine in a single-blind design. All subjects showed increased systolic/diastolic blood pressure and improved continuous performance task scores after dextroamphetamine. Global and regional metabolic rates were not significantly altered by the stimulant. When regional and global rates were normalized, the metabolic rates of only three cortical regions differed significantly between conditions. Individually, global metabolism increased in 4 subjects, was unchanged in 2, and decreased in 2 after stimulant infusion. No clinical characteristics differentiated these patients. I.V. infusion of dextroamphetamine did not significantly alter brain metabolism in ADHD adults in this preliminary study.

Adult↗
PubMed1993

Attention deficit-hyperactivity disorder in people with generalized resistance to thyroid hormone.

BACKGROUND: Attention deficit-hyperactivity disorder is a well-recognized psychiatric disorder of childhood. Its cause is unknown, but there is evidence of a familial predisposition. Symptoms suggestive of this disorder have been reported in subjects with generalized resistance to thyroid hormone, a disease caused by mutations in the thyroid receptor-beta gene and characterized by reduced responsiveness of peripheral and pituitary tissues to the actions of thyroid hormone. We systematically evaluated the presence and severity of attention deficit-hyperactivity disorder in 18 families with a history of generalized resistance to thyroid hormone. METHODS: We studied 49 affected and 55 unaffected family members; 52 were adults, and 52 were children. All subjects were evaluated with structured psychiatric questionnaires by interviewers who were unaware of the medical diagnosis. The number of symptoms of attention deficit-hyperactivity disorder was calculated for each subject. RESULTS: Among the adults, 11 of 22 subjects with generalized resistance to thyroid hormone (50 percent) and 2 of 30 unaffected subjects (7 percent) had met the criteria for attention deficit-hyperactivity disorder as children (P < 0.001). Among the children, 19 of 27 subjects resistant to thyroid hormone (70 percent) and 5 of 25 unaffected subjects (20 percent) met the criteria for the disorder (P < 0.001). The odds of having attention deficit-hyperactivity disorder were 3.2 times higher for affected male subjects than for affected female subjects and were 2.7 times higher for unaffected male subjects than for unaffected female subjects. The mean symptom score was 2.5 times higher in the affected group than in the unaffected group (7.0 vs. 2.8, P < 0.001). The frequency of other psychiatric diagnoses was similar in the two groups. CONCLUSIONS: In our study sample, attention deficit-hyperactivity disorder is strongly associated with generalized resistance to thyroid hormone.

Adult↗
PubMed1993

Effects of acute stimulant medication on cerebral metabolism in adults with hyperactivity.

Recent work in our laboratory has demonstrated both global and regional reductions in cerebral glucose metabolism in adult subjects with attention-deficit hyperactivity disorder (ADHD). The purpose of the present study was to examine the effects of an acute dose of stimulant medication on cerebral metabolism in adults with ADHD using positron emission tomography with fluorodeoxyglucose-18 as the tracer. Each subject underwent scanning twice, once off-drug and again after receiving a single oral dose of either dextroamphetamine (0.25 mg/kg) or methylphenidate (0.35 mg/kg). Subjects completed behavioral self-report measures before and after the scan and performed an auditory continuous performance task during the tracer uptake period. Neither drug changed global metabolism. Both drugs increased systolic blood pressure, and dextroamphetamine improved performance on the auditory attention task. Each stimulant produced a differential pattern of increases and decreases in regional metabolism throughout the regions of interest that were sampled. Rather than increasing glucose utilization in specific brain regions with lowered metabolic rates in adults with ADHD, stimulants may act by altering glucose use throughout the brain.

Adult↗
PubMed1992

Regulation of sociosexual communication in female Long-Evans rats by ovarian hormones.

Two experiments examined the role of the steroid hormones, estradiol (E2), progesterone (P), and testosterone (T), in activating scent marking and 50-kHz ultrasonic vocalizations in ovariectomized Long-Evans rats in response to a devocalized male rat. In Experiment 1, females received, in a counterbalanced order, a series of six hormone treatments consisting of two injections (48-54 and 4 hr before behavioral tests). The six treatments were 8 micrograms E2 followed by 500 micrograms P or oil, 2 micrograms E2 followed by 500 micrograms P or oil, and oil followed by 500 micrograms P or oil. Injections of either the high or low dose of E2 followed by P resulted in high levels of vocalizations. Neither E2 by itself or P by itself were very effective. Surprisingly, none of the hormone treatments were effective in activating marking above the level seen when the females received control injections of oil. Four other hormone treatments were examined in Experiment 2: daily injections of 500 micrograms T, daily injections of 50 micrograms E2, implantation of silastic capsules of E2 (5% E2, 5 mm length) followed by 500-micrograms P injections before behavioral tests, and implantation of silastic capsules of E2 followed by oil injections. Animals receiving E2 by silastic capsule followed by P injection displayed the highest levels of marking and vocalizations across the five weekly tests. These results suggest that while E2 and P synergize for the display of female-typical behaviors similar to the hormonal regulation of lordosis, the mechanism of E2 action may be different for the two signaling behaviors. Scent marking appears to be responsive to the tonic levels of E2 released from silastic capsules.

Animals↗
PubMed1992

Intracranial androgenic and estrogenic stimulation of male-typical behaviors in house mice (Mus domesticus).

Two experiments in house mice (Mus domesticus) examined the neural sites at which steroid hormones activate the following male-typical behaviors: 70 kHz ultrasonic mating vocalizations in response to stimulus females or their urine, urinary marking in response to stimulus males or stimulus females, mounting of estrous females, and intermale aggression. In the first experiment, four groups of castrated males received bilateral intracranial implants of testosterone (T) into either the septum (SEPTUM), medial preoptic area (MPO), anterior hypothalamus (AHA), or ventromedial hypothalamus (VMH). Two control groups received subcutaneous silastic capsules of T (TSIL) or empty silastic capsules (BSIL). The TSIL males performed all behaviors at male-typical levels while the BSIL males were unresponsive. MPO males emitted ultrasonic mating vocalizations at high levels while few vocalizations were seen in males of the other brain implant groups. The VMH, AHA, and MPO males urine marked at higher levels than the BSIL males but did not exhibit the high levels of the TSIL males. Mounting was observed only in MPO and TSIL males. Aggression was rare in males from any of the brain implant groups. In the second experiment, the hormone activity of the implants was increased by using testosterone propionate (TP) or a 50% mixture of estradiol (E2) and cholesterol. The six groups were SEPTUMTP, SEPTUME2, MPOTP, MPOE2, TPSIL, and BSIL. The TPSIL males performed all behaviors at male-typical levels while the BSIL males were unresponsive. TP was effective at restoring vocalizations and urine marking only when placed in the MPO; however, E2 was effective at both sites. Again aggression and mounting were less evident in the brain implanted males. In conclusion, implants of T or TP were effective in restoring ultrasonic mating vocalization when placed into the MPO. MPO implants of T and TP were also effective in stimulating urine marking, although VMH and AHA implants also showed some effectiveness. The restorative effects of E2 were not localized which is probably related to the greater hormonal activity of this treatment. Comparisons of the properties of the various brain implants to restore more than one behavior were discussed.

Aggression↗
PubMed1992

Variations in scent marking and ultrasonic vocalizations by Long-Evans rats across the estrous cycle.

The purpose of the present study was to investigate whether the signaling behaviors of female Long-Evans rats varies over the estrous cycle. Scent marking and 50-kHz ultrasonic mating vocalizations, in response to a devocalized sexually experienced male, changed in frequency across the cycle, both behaviors being highest at proestrus/early estrus. Vocalizations were recorded on every day of the cycle and also in females showing no regular cycles. In contrast, scent marking was rarely observed during the estrous cycle except at proestrus/early estrus. These results suggest that both behaviors, which increase around the time of sexual receptivity, may help to coordinate reproduction and further suggest an endocrine basis for the changes observed over the estrous cycle.

Animal Communication↗
PubMed1991

Hormonal control of precopulatory sebaceous scent marking and ultrasonic mating vocalizations in male rats.

The effects of testosterone (T) and its major metabolites, estradiol (E2) and dihydrotestosterone (DHT), on the restoration of sebaceous scent marking and 50-kHz ultrasonic vocalizations in male rats were measured in two studies (Experiments 1 and 2) employing different hormone levels. Silastic capsule administration of high and low doses of T (10 and 20 mm) or E2 (5%; 5 and 10 mm) completely restored marking to precastration levels. Both doses of DHT (30 and 40 mm) or no hormone replacement were without effect when tested in presence of estrous odor cues. In our testing paradigm, males appeared to mark glass objects with a sebaceous secretion rather than urine. Only the high dose of T (20 mm) restored vocalizations to intact levels, while animals receiving the high or low dose of E2 or DHT showed no restoration of behavior. In Experiment 3, habituation to estrous odor cues over weekly tests was not observed for marking or vocalizations. These results are discussed with respect to similarities and differences in the hormonal control of signaling behaviors by androgen metabolites in male rodents.

Animals↗
PubMed1991

A brain atlas of the northern fulmar (Fulmarus glacialis) in stereotaxic coordinates.

The brain of a procellariiform bird, the Northern Fulmar (Fulmarus glacialis), is presented in the form of a stereotaxic atlas. The Northern Fulmar is especially interesting because both field and laboratory evidence support olfaction as one of its major sensory systems. The nasal cavity and olfactory bulb of most procellariiforms are among the largest of all avian orders; the central olfactory pathways may be more extensive as well. A brain atlas of the Northern Fulmar, a relatively accessible procellariiform species on which several studies have already been done, can provide reference for research both on neural mechanisms underlying olfaction and on comparative neuroanatomical data within Aves and between avian and nonavian groups.

Animals↗
PubMed1990

Correlation of dopamine release in the nucleus accumbens with masculine sexual behavior in rats.

Extracellular dopamine (DA) and 3,4-dihydroxyphenylacetic acid (DOPAC) in the nucleus accumbens (N. Acc.) were measured by in vivo microdialysis during male sexual activity. DA and DOPAC were significantly increased during copulation, but not during mild tail pinch. These results are consistent with studies showing increases in N. Acc. DA associated with positively reinforcing environmental stimuli.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1988

Role of the main olfactory system in recognition between individual spiny mice.

Recognition between spiny mice requires a period of exposure to learn the olfactory cues of individual conspecifics that can serve as recognition signatures in subsequent discrimination. Animals received nasal irrigations of zinc sulfate to disrupt sensory input to the main olfactory system (MOS) either prior to the 9-day exposure period (Experiment 1) or immediately after the exposure period (Experiment 2). Animals rendered anosmic by zinc sulfate did not show evidence of recognition as defined by huddling preferences. In contrast, animals who received irrigations of saline were able to preferentially huddle with their cagemate who they had been housed with during the exposure period. The results suggest that the MOS is necessary in mediating behavioral discrimination between conspecifics.

Animals↗
PubMed1986

Physical and behavioral sequelae of low birthweight in spiny mice (Acomys cahirinus).

Physical and behavioral sequelae of low birthweight (LBW) were investigated in spiny mice (Acomys cahirinus). When raised by their biological mother, pups whose Day-2 weights were 1 SD or more below the population mean remained smaller through the first 30 days postpartum than pups born within normal (N) weight ranges. LBW pups fostered onto mothers who gave birth to N pups gained weight more rapidly than LBW pups remaining with their own mother. Similarly, N pups fostered onto mothers of LBW pups displayed reduced weight gain relative to N siblings raised by their biological mother. It appears that rate of weight gain is influenced by an interaction between birthweight and maternal rearing environment. LBW pups also were less responsive than N pups to maternal chemical cues, indicating that low birthweight is correlated with deficits in adaptive behavior.

Animals↗
PubMed1986

Short photoperiods increase ultrasonic vocalization rates among male Syrian hamsters.

Two experiments investigated the effects of daylength on the emission of 35 kHz ultrasonic (US) calls among male hamsters. In Experiment 1, castrated males received Silastic implants subcutaneously that contained either low doses of testosterone in oil or oil alone; US calls were recorded when these males were paired with receptive females. Males exposed to eight hours of light per day (short photoperiod) called more often than males exposed to fourteen hours of light per day (long photoperiod). This was true whether or not they received testosterone. In Experiment 2, a similar testing and photoperiod exposure paradigm was used, but the subjects were gonadally intact. Among males exposed to short photoperiods, US call rates increased while endogenous testosterone levels decreased. In contrast, hamsters exposed to long photoperiods maintained stable calling rates and testosterone levels. These findings are related to recent studies concerning the neural mechanisms that regulate ultrasonic vocalizations and to the possible role of photoperiod in modulating conspecific aggression.

Animals↗