Reflections on research

The authors present their reflections on several of the major topics related to research. The subjects discussed include the quantity and quality of research; the motivation for research; the research process; research paradigm; restraints of research; and freedom to research. They point out that the haste to achieve success and to publish in most cases has precluded the learning process about the substance and methodology of research. An attempt is made to relate general problems of research and its methodology to research in the area of congenital facial deformities.

Serial measurement of blood flow in expanded tissue by laser Doppler velocimetry

This study provides additional information about changes in blood flow in expanded tissue as measured by laser Doppler. Five one-kilogram albino Hartley guinea pigs were implanted with commercially available hemispheric expanders. The expanders were inflated every 3 days on four successive occasions. Blood flow measurements were taken on each animal just before each inflation, immediately after inflation, and then at 1, 2, 3, 4, and 24 hours after expansion. Measurement of flow changes immediately after each inflation of the expander showed that, initially, blood flow in the tissue overlying the expander recovered quickly, but as the expansion process was continued, the flow did not return to baseline values so rapidly. This might be an indication that tissue expansion in patients could be carried out more rapidly during the initial inflations, with increasing recovery periods between inflations as the expansion process continued.

Does interference with mucoperiosteum and palatal bone affect craniofacial growth? An experimental study in beagles

This study was designed to assess the effects of raising mucoperiosteal flaps and exposing palatal bone at the time of palatoplasty. Using 62 beagle puppies as subjects, we tested the hypothesis that raising mucoperiosteal flaps does not interfere with craniofacial growth. We further hypothesized that the size of the area of bone exposed following palatoplasty does affect subsequent craniofacial growth. The animals were divided into four groups: two control groups (unoperated and unrepaired) and two experimental groups. In the first experimental group, two-flap palatoplasty was used to close the surgically induced palatal defect, leaving narrow strips (0 to 2.5 mm) of bone exposed lateral to the flaps. In the second group, one flap was raised to close the defect, leaving a wide area (5 to 6 mm) of palatal bone exposed on one side. Thirty-four direct craniometric measurements were analyzed. Animals that had elevation of both mucoperiosteal flaps with narrow strips of denuded bone on both sides had less severe craniofacial growth aberrations than those in which the defect was left unrepaired or was repaired with one mucoperiosteal flap leaving a wider area of bare bone exposed. These findings suggest that raising mucoperiosteal flaps is less detrimental to craniofacial growth than leaving large areas of exposed palatal bone.

Electrophysiology and anatomy of medulla interneurons in the optic lobe of the cockroach, Periplaneta americana

1. Medulla interneurons of the optic lobe of P. americana were studied to determine their spectral properties. These neurons exhibited tonic firing which changed with monochromatic broadfield illumination of the ipsilateral eye. The response patterns of these neurons were analyzed by inferring their relation to the ultraviolet (UV) and green (G) photoreceptor groups of the eye. Their anatomy was described after injection of Lucifer yellow. 2. Broadband neurons received either excitatory or inhibitory input from both UV and G receptors. These neurons were not strictly sensitive to luminosity levels and had large cell bodies in the central rind of the medulla and wide dendritic arbors in the medulla neuropil. 3. Narrow band neurons received input from predominantly one receptor type. Their spectral sensitivity curves were more finely tuned than those of the primary receptors presumably due to neural interactions within the optic lobe. 4. Color opponent neurons were inhibited by UV and excited by G inputs in their sustained response. Under certain conditions, some of these neurons also showed G inhibition. These neurons suggested the presence of a subsystem involved in color vision. 5. Broadband, narrow band and color opponent properties were seen in some single neurons when tested over a 5-6 log unit range of intensity. The responses of some of these neurons changed when stimulus duration was increased. These findings indicated that functional classification for these neurons was dependent on stimulus intensity and duration. 6. Polarizational sensitivity was tested in preliminary experiments. Two neurons responded to the movement and direction of polarized light.

Multivessel coronary angioplasty early after acute myocardial infarction

Coronary angioplasty has been applied in patients with recent myocardial infarction, but results of angioplasty of multiple vessels early after myocardial infarction in patients with severe multivessel disease have not been reported. Coronary angioplasty of multiple vessels was performed in 105 patients 0 to 15 days (mean 5 +/- 4) after recent myocardial infarction. There were 77 men (73%) and 28 women (27%), with a mean age of 57 years. All patients had severe multivessel disease, 68% with two vessel and 32% with three vessel disease. Twenty-eight patients (27%) had successful thrombolysis before angioplasty and 70 (67%) had postinfarction angina. Mean left ventricular ejection fraction was 58 +/- 10% and was less than 45% in 13 patients (12%). Angioplasty was attempted in 319 lesions (mean 3 lesions per patient, range 2 to 9) and 252 vessels (mean 2.4 vessels per patient, range 2 to 4), with success in 302 lesions (95%) and 237 vessels (94%); angioplasty was done in two stages in 59 patients (56%). Clinical success was achieved in 102 patients (97%). Complications included myocardial infarction in six patients (5.7%) (one Q wave, five non-Q wave), urgent bypass surgery in two (1.9%) and death in one (0.9%); overall, seven patients (7%) had a major complication. All patients had a follow-up duration greater than 1 year (mean 31 months, range 12 to 73). Clinical recurrence developed in 24 patients (23%), of whom 21 had repeat angioplasty, 1 had bypass surgery and 2 were managed medically. Ten patients (9.8%) had a late infarction and 5 (4.9%) died of cardiac death during the follow-up period.(ABSTRACT TRUNCATED AT 250 WORDS)

Valproic acid selectively reduces the low-threshold (T) calcium current in rat nodose neurons

Valproic acid (VPA) is an antiepileptic drug used in the treatment of a wide variety of human seizures including generalized absence (GA) (petit mal) seizures. The mechanism of action of VPA in controlling GA seizures is not known. We tested the effects of VPA on the Ca2+ current components of acutely dissociated rat nodose ganglion neurons. VPA reduced the low-threshold (T) Ca2+ current at clinically relevant concentrations but had no effect on the high-threshold (N and L) current components. The effect on T current was concentration-dependent and most apparent at peak current. There was little effect seen on late current. VPA did not affect the rate or voltage-dependency of T current activation. The selective reduction of T current may be a means by which VPA is effective in controlling GA seizures.

Multiple intracerebral hemorrhages after smoking "crack" cocaine

After smoking "crack" cocaine and consuming large quantities of ethanol, a 36-year-old man developed multiple, bilateral, deep, and superficial cerebral hematomas. He was hypertensive for several days, but angiography revealed no evidence of vascular malformation or vasculitis. The multifocality of the hematomas and lack of underlying disease suggest that the hemorrhages resulted from cocaine-induced acute hypertension or arterial spasm, possibly potentiated by heavy ethanol consumption.

Fostering self-help on an inpatient unit

A self-help movement for people with chronic mental illness is growing but is not as advanced as the system of self-help for the chemically dependent. Barriers to organized self-help among those with chronic mental illness include stigma, denial, and the debilitating effects of the illnesses themselves. The authors developed a coping group on a 12-bed psychiatric unit to address these problems. The group was designed to strengthen ties with a local self-help club and to foster the idea that people with chronic mental illness can have a positive impact on the course of their illness. Mental health consumers who were successfully coping with their illnesses were guest speakers and role models for group members. The coping group, which was well received by participants, stimulated research questions and suggested potential modifications of clinical practice. In recent years, a mental health consumer movement has gathered momentum. Individuals who have been receiving psychiatric services are now clamoring for a more active role. There are currently several national consumer organizations that are growing in power and visibility. Some self-help groups, like Recovery Inc., are primarily therapy groups concerned with personal growth. Others, like the National Mental Health Consumers Association, are involved in supporting research and empowerment through political action as well as focusing on mutual-aid groups.

Enhancement of expansion of guinea pig skin by local delivery of an anticontractile agent using a new bilumen expander

We have shown previously that anticontractile agents used with tissue expanders provide significantly more rapid expansion in an animal model than in controls without these agents. We describe an improved method of delivery involving a perforated concentric envelope enclosing a tissue expander (type 2) in place of the single circumferential perforated catheter (type 1) used previously by us. Eleven guinea pigs received a type 1 expander and ten received a type 2 expander. The anticontractile agent theophylline was delivered in saline around each expander, and all the expanders from both groups were inflated to a similar pressure every three days for twelve days. Significantly greater expansion, in terms of total volume delivered to the expander, was noted using the type 2 expander. We conclude that the concentric device offers further improvement, probably as a result of more uniform distribution of the agent in the tissue around the expander.

The hemodynamic effects of intravenous ranitidine in intensive care unit patients: a double-blind prospective study

The hemodynamic effects of intravenous ranitidine were studied in a prospective double-blind fashion in postoperative intensive care unit patients to determine if this H2 blocker produced the same transient fall in mean arterial pressure and systemic vascular resistance known to occur with cimetidine infusion. We found no statistically significant hemodynamic changes from baseline associated with infusion of 50 mg ranitidine over a 5-minute period. The different chemical ring structure of ranitidine and its effect on H2 vascular and cardiac receptors may account for these observations.

The influence of lip repair with and without soft-tissue undermining on facial growth in beagles

The present study was designed to test the hypothesis that undermining of the soft tissues on the surface of the maxilla at the time of lip repair in unilateral cleft lip, alveolus, and palate results in more severe craniofacial growth aberrations than lip repair alone. Sixty-seven purebred beagles were used in this experiment. The animals were divided into four groups: two control groups (unoperated and unrepaired) and two experimental groups (lip repair without undermining and lip repair with undermining). Lip pressures were monitored in all groups. Significantly higher lip pressures were observed in animals with soft-tissue undermining. Cephalometric measurements were analyzed using univariate and multivariate techniques. The results of this study indicate that lip repair performed with soft-tissue undermining results in more severe craniofacial growth aberrations than lip repair performed alone.

Effects of sodium bicarbonate in canine hemorrhagic shock

We studied the use of sodium bicarbonate administration in a canine model of hemorrhagic shock to determine its effect on hemodynamics, arterial and venous blood gases, respiratory gases, and blood lactate levels. Thirteen dogs were anesthetized, paralyzed, mechanically ventilated, and hemodynamically monitored. Hypotension was induced and maintained at a mean arterial pressure of 40 to 45 mm Hg using controlled hemorrhage and reinfusion. After 2.5 h of shock, the dogs were randomized into two groups: one group (n = 6) received NaCl infusion; the other (n = 7) received sodium bicarbonate (1 mEq/kg followed by a continuous infusion of 2.5 mEq/kg.h for 2.5 h). CO2 production was increased in the alkali group, but there was no statistically significant difference between groups in any measured hemodynamic, blood gas, or respiratory gas variable. These included heart rate, BP, cardiac output, arterial and venous pH, CO2 production, and bicarbonate levels. Blood lactate levels, however, in the bicarbonate treated animals were significantly (p less than .01) higher than in the group treated with NaCl alone (10.1 +/- 3.2 vs. 5.1 +/- 1.2 mEq/L). These results are similar to the effects of bicarbonate found in other models of lactic acidosis, and suggest that bicarbonate therapy may have limited usefulness in the treatment of lactic acidosis.

Simultaneous cleft lip and palate repair: an experimental study in beagles

This study was designed to test the hypothesis that simultaneous lip and palate repair results in more severe craniofacial growth aberrations than lip repair or palate repair performed separately. Seventy-six purebred beagles were divided into five groups. Two of these groups were controls (unoperated and unrepaired animals); the three remaining groups were experimental (in one group only the lip was repaired, in another only the palate was repaired, and in the last the lip and palate were repaired simultaneously). Cephalometric measurements were analyzed using univariate and multivariate statistical techniques. In multivariate analysis, stepwise multiple regression and discrimination were applied to precisely assess the effects of the various surgical procedures. The results of this study indicate that simultaneous lip and palate repair results in more severe craniofacial growth aberrations than lip repair or palate repair performed separately.

Triple vessel coronary angioplasty: acute outcome and long-term results

Triple vessel coronary angioplasty, defined as angioplasty of one or more lesions in each of the three major coronary arteries (left anterior descending, left circumflex, right coronary artery) was performed in 50 (11%) of 469 patients who had angioplasty of multiple vessels. There were 32 men and 18 women with a mean age of 56 years. All 50 patients had severe three vessel coronary disease and represent approximately 5% of patients with three vessel disease who had revascularization in this institution; 8 (16%) had previous coronary bypass surgery, and 23 (46%) had previous myocardial infarction. Unstable angina was present in 33 patients (66%) and 96% had Canadian Heart Association class III or IV angina; mean left ventricular ejection fraction was 57 +/- 11%. Angioplasty was performed in 176 vessels (3.5 vessels per patient, range 3 to 6) and in 250 lesions (5 lesions per patient, range 3 to 9); angiographic success was achieved in 240 lesions (96%) and 166 vessels (94%). Success in all vessels attempted was achieved in 40 (80%) of the 50 patients. Clinical success (angiographic success associated with clinical improvement) was obtained in all 50 patients in whom triple vessel angioplasty was performed; none of them required urgent bypass surgery and 5 patients (10%) had a non-Q wave myocardial infarction. In four other patients triple vessel angioplasty was planned but not performed because of failure to dilate the primary vessel; urgent bypass surgery was required in one of these, who developed a Q wave infarction. Thus, overall clinical success in 54 patients was 93%; the incidence rate of myocardial infarction was 11%, and that of urgent surgery 1.8%.(ABSTRACT TRUNCATED AT 250 WORDS)

Role of animal models in experimental studies of craniofacial growth following cleft lip and palate repair

The present study was designed to examine the role of the animal model on investigations of craniofacial growth. Identical experimental protocols were followed using 6-week-old rabbits and 8-week-old beagles. Three groups were used for each species, two control groups and one experimental group. The groups within each experimental model were compared for lip pressure, occlusion, and cephalometrics. Statistical analyses including analyses of correlations were used to evaluate dimensional craniofacial relations. The results of this study revealed that dimensional relations were significantly different in rabbits and beagles despite the similarities observed in overall craniofacial growth aberrations. Analysis of the results does not allow strong conclusions about which animal model (rabbits or beagles) is more appropriate for studying craniofacial growth.

Use of percutaneous gastrostomy in the intensive care patient

We evaluated the use of percutaneous endoscopic gastrostomy in 30 ICU patients. There was a 14% incidence of minor complications, no major complications, and no mortality. We conclude that percutaneous endoscopic gastrostomy is a useful alternative to operative gastrostomy in the ICU patient.

A simple technique to accurately determine intra-abdominal pressure

The determination of intra-abdominal pressure (IAP) may be useful in a variety of clinical situations. Despite this, invasive IAP monitoring is seldom performed due to the risks involved. Using a standard canine model of increased IAP, we evaluated the accuracy of transurethral bladder catheter pressure in reflecting IAP. Throughout the range of IAP studied (10 +/- 5 to 70 +/- 10 mm Hg), bladder pressure did not differ significantly from the direct measurement of IAP. We conclude that the measurement of bladder pressure using a standard transurethral bladder catheter provides an accurate determination of IAP.

Naloxone in renal ischemia: a functional and microanatomical study

Naloxone HCl (Nx) improves cardiopulmonary performance, reverses cellular hypoxia, and stabilizes lysosomal membranes in shock states. However, no detailed study has yet explored its potential role in renal ischemia, which is inevitable in transplantation and surgical and nonsurgical conditions associated with hypotension and shock. This functional and microanatomical study was carried out on dogs subjected to renal warm ischemia with contralateral nephrectomy. Group I (control; N = 4) had bilateral renal dissection and right nephrectomy. Groups II-IV had their kidney pedicles cross-clamped for 60 min and then reperfused. Group II (N = 9) ischemic kidneys received no treatment. Group III (N = 6) kidneys were flushed with pure Nx HCl (2 mg/kg) during ischemia. Group IV (N = 6) dogs received one iv Nx bolus (2 mg/kg) before clamping and another dose before declamping. Biopsies for adenine nucleotides, histology, and ultrastructure were obtained before ischemia, before reflow, and 15 min and 7 days after reflow. Serum creatinine and blood urea nitrogen were measured daily. Ischemia induced significant renal dysfunction, which was reversed by systemic Nx. Nx offered a remarkable protection against postischemic structural damage. Seventy percent of Group II cortical sections showed grade 4 acute tubular necrosis (ATN), and severe residual damage after a week. Eighty-three percent of Group IV sections showed grade 1 ATN and no residual damage after a week. One week survival was 33% in Group II and 100% in Group IV. Nx can be useful in prevention of acute renal failure in clinical situations with arterial hypotension and shock.

Multimodal sensory discrimination deficits in Korsakoff's psychosis

A consistent impairment in odor identification was observed among a group of 21 amnesic patients, diagnosed as having Korsakoff's psychosis. In a subsequent study of eight Korsakoff and matched alcoholic control subjects, a comparable olfactory deficit was again demonstrated, as well as impairment in color discrimination and auditory perception. No such deficit was observed for a picture identification task designed to control for the non-sensory demands of the olfactory test. Stepwise multiple regression analysis showed a significant correlation between odor identification scores and the concentration of the primary metabolite of norepinephrine in lumbar cerebrospinal fluid. The data demonstrate a consistent coincidence between memory impairment and deficient sensory perception among patients with Korsakoff's psychosis.

Hyperdense renal masses: a CT manifestation of hemorrhagic renal cysts

Eleven patients with sharply circumscribed round to ovoid renal cysts measuring 70-90 H on CT are reported. The cysts were hyperdense on unenhanced scans, measuring 30-60 H greater than the adjacent parenchyma, and either hypodense, isodense, or hyperdense on enhanced scans. Four patients had polycystic kidney disease; of the other 7 patients, the cysts were cortical in 6 and parapelvic in 1. Eight patients had a solitary cyst and 3 had multiple cysts. Sonography demonstrated internal echoes and/or lack of increased through-transmission in 6 patients. Pathological analysis was available in 6 cases and indicated a benign, hemorrhagic renal cyst. This hyperdense CT appearance is characteristic of some hemorrhagic renal cysts, though differentiation between benign and malignant cysts requires cyst puncture and/or surgery.

Communicative behavior of adults with an autistic four-year-old boy and his nonhandicapped twin brother

Sixteen female preschool teachers were videotaped playing in dyads with a nonverbal, socially unresponsive autistic 4-year-old boy and his nonhandicapped fraternal twin brother. Eight adults were informed that the autistic child had a language disability and did not talk or understand much language; eight adults were not informed about any differences between the children. Language to the autistic child was simpler, more concrete, and more often accompanied by gestures than language to his brother for both groups of subjects. Informed teachers made greater speech modifications to the autistic child and were more successful at keeping him on-task than uninformed adults. The theoretical and practical implications of communicative adjustments to children with language and social impairments are discussed.