Isometric force-related activity in sensorimotor cortex measured with functional MRI

Isometric force-related functional magnetic resonance imaging (fMRI) signals from primary sensorimotor cortex were investigated by imaging during a sustained finger flexion task at a number of force levels related to maximum voluntary contraction. With increasing levels of force, there was an increase in the extent along the central sulcus from which a fMRI signal could be detected and an increase in the summed signal across voxels, but these parameters were related in such a way that the signal from each voxel was similar for each level of force. The results suggest that increased neuronal firing and recruitment of corticomotor cells associated with increased voluntary isometric effort are reflected in an expansion of a relatively constant fMRI signal over a greater volume of cortex, rather than an increase in the magnitude of the response in a particular circumscribed region, possibly due to perfusion of an increase in oxygen-enriched blood over a wider region of the cortex.

The moderating influence of physical fitness on age gradients in vigilance and serial choice responding tasks

The moderating influence of physical fitness on age gradients in measures obtained from vigilance and serial choice responding tasks is examined in a sample of 90 postal workers. Physiological data relating to aerobic fitness determined fitness level within 2 age groups: younger participants ages 18 to 30 years (M = 25.19; 24 men, 24 women) and older participants ages 43 to 62 years (M = 49.19; 20 men, 22 women). A performance decrement across time was found in several measures, and some variation as a function of age was apparent. However, post hoc statistical analyses did not indicate this was due to older adults underperforming younger adults. According to predictions, significant Age x Fitness interactions showed older less fit workers to consistently underperform other participants. The findings suggest that older less fit individuals have lower signal sensitivity and processing speed than older fitter people and younger individuals. Results are discussed in relation to underlying physiological mechanisms.

Physical and sexual abuse of children in the West Midlands

OBJECTIVE

To describe the convicted and cautioned abusers and the nature of the physical and sexual abuse of children using a legal classification in an attempt to formulate operational criteria for future comparative studies.

DESIGN

A retrospective sequential survey of all cautioned and convicted physical and sexual abusers between the January 1, 1988 and June 30, 1994.

SETTING

The West Midlands police jurisdiction.

SUBJECTS

1,113 abused children and 964 abusers.

RESULTS

The majority of all abuse involved a single child. Many abusers lived in the same household and were in a position of trust or quasi-trust. When strangers committed abuse, the majority of abuse was sexual. A third of the abusers were unemployed. Multiple abuse tended to be sexual and was perpetrated by men. The physical abuse of young children tended to be committed by younger women. No women over the age of 40 had sexually abused a child. Of the children under 12 months, 1.5% had been sexually abused and 8.5% had been physically abused. The greater proportion of physical abuse had occurred in children under 9 years of age whereas sexual abuse was perpetrated more often in girls aged 9 to 11 years. No girls were murdered in this survey. Significantly more boys had been buggered.

CONCLUSION

This preliminary study is representative of all the cautioned and convicted cases within the selected 5-year period and obtained from a source of material hitherto unavailable. Many of the findings of this preliminary study are in line with previous studies. Substantial descriptive information has been obtained on a selected population of cautioned or convicted abusers. Further studies may indicate that the cautioned and convicted are more representative of abusers generally than previously thought. Expanded studies may eventually produce particularized profiles of both abusers and the abused, but even the limited guidance provided by this preliminary study will give some assistance to law enforcement agencies in detection and child protection agencies in identifying children at risk and targeting resources more efficiently.

The moderating influence of physical fitness on age gradients in vigilance and serial choice responding tasks

The moderating influence of physical fitness on age gradients in measures obtained from vigilance and serial choice responding tasks is examined in a sample of 90 postal workers. Physiological data relating to aerobic fitness determined fitness level within 2 age groups: younger participants ages 18 to 30 years (M = 25.19; 24 men, 24 women) and older participants ages 43 to 62 years (M = 49.19; 20 men, 22 women). A performance decrement across time was found in several measures, and some variation as a function of age was apparent. However, post hoc statistical analyses did not indicate this was due to older adults underperforming younger adults. According to predictions, significant Age x Fitness interactions showed older less fit workers to consistently underperform other participants. The findings suggest that older less fit individuals have lower signal sensitivity and processing speed than older fitter people and younger individuals. Results are discussed in relation to underlying physiological mechanisms.

Hepatic kinetics and magnetic resonance imaging of gadolinium-EOB-DTPA in dogs

RATIONALE AND OBJECTIVES

To measure the hepatic uptake and biliary elimination kinetics of gadolinium (Gd)-EOB-DTPA in dogs.

METHOD

Two groups of four beagles each were anesthetized and given an intravenous bolus of 25 mumol/kg or 250 mumol/kg of Gd-EOB-DTPA. Blood, hepatic bile, and urine were collected over 140 minutes, and liver samples were obtained immediately after the dogs were killed. Conventional T1-weighted spin echo sequences of the liver were performed on a 1.5-Tesla (T) magnetic resonance imager during sampling. A ninth beagle received a bolus of 25 mumol/kg followed 140 minutes later with a bolus of 250 mumol/kg of Gd-EOB-DTPA. Wedge liver biopsies were obtained for Gd estimation at various times after dosing, and Gd concentration was measured by inductively coupled plasma atomic emission spectroscopy.

RESULTS

The plasma concentration of Gd-EOB-DTPA decreased in a biexponential manner with half-lives of approximately 4 minutes and 60 minutes for the distribution and elimination phase independent of the dose given. Gadolinium bile concentration reached peak values between 80 and 140 minutes: 6.3 +/- 1.6 mmol/L for the low dose (LD) and 11.6 +/- mmol/L for the high dose (HD). Bile Gd output was 62.0 +/- 8.8 (LD) and 78.3 +/- 30.2 (HD) nmol/minute-kg 50 to 80 minutes after injection. Gadolinium-EOB-DTPA was excreted by the biliary route to 24.8 +/- 2.6 (LD) and 3.6 +/- 1.2 (HD) percent of the dose within 140 minutes. Liver Gd concentration was 0.43 +/- 0.14 (LD) and 4.3 +/- 0.5 (HD) mmol/kg liver tissue at the conclusion of the studies. Calculated concentrations in the hepatocyte were 60 (LD) and 15 (HD) times higher than in plasma at 25 minutes after dosing. Whereas the low dose exhibited excellent contrast enhancement for the whole period, the high dose displayed a biphasic signal enhancement with a decreasing signal caused by the too-high hepatic gadolinium accumulation.

CONCLUSIONS

Transport of the Gd-EOB-DTPA into the hepatocyte exceeded elimination from hepatocyte to bile. The high dose defined a biliary transport maximum for Gd-EOB-DTPA of 78.3 +/- 30.2 nmol/minute-kg. The liver accumulation results from fast transport into the hepatocyte and rate-limited slower transport from hepatocyte to bile. The accumulation occurs against a strong concentration gradient, suggesting energy-dependent active transport into the hepatocyte.

Lightwand intubation: II--Clinical trial of a new lightwand for tracheal intubation in patients with difficult airways

Lightwands have been used to assist in the tracheal intubation of patients with difficult airways for many years. A new lightwand (Trachlight) with a brighter light source and a flexible stylet permits both oral and nasal intubation under ambient light. This study reports the effectiveness of the Trachlight in tracheal intubation in patients with difficult airways. Two groups of patients were studied: Group 1--patients with a documented history of difficult intubation or anticipated difficult airways; Group 2--anaesthetized patients with an unanticipated failed laryngoscopic intubation. In Group 1, the tracheas were intubated using the Trachlight with patients either awake or under general anaesthesia. In Group 2, tracheas were intubated under general anaesthesia using the Trachlight. The time-to-intubation, number of attempts, failures, and complications during intubation for all patients were recorded. Two hundred and sixty-five patients were studied with 206 patients in Group 1, and 59 in Group 2. In most patients, the tracheas were intubated orally (183 versus 23 nasal) during general anaesthesia (202 versus 4 awake) in Group 1. Intubation was successful in all but two of the patients with a mean (+/- SD) time-to-intubation of 25.7 +/- 20.1 sec (range 4 to 120 sec). The tracheas of these two patients were intubated successfully using a fibreoptic bronchoscope. Orotracheal intubation was successful in all patients in Group 2 using the Trachlight with a mean (+/- SD) time-to-intubation of 19.7 +/- 13.5 sec. Apart from minor mucosal bleeding (mostly from nasal intubation), no serious complications were observed in any of the study patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical trial of a new lightwand device (Trachlight) to intubate the trachea

BACKGROUND

Transillumination of the soft tissue of the neck using a lighted stylet (lightwand) is an effective and safe intubating technique. A newly designed lightwand (Trachlight) incorporates modifications to improve the brightness of the light source as well as flexibility. The goal of this study was to determine the effectiveness and safety of this device in intubating the trachea of elective surgical patients.

METHODS

Healthy surgical patients were studied. Patients with known or potential problems with intubation were excluded. During general anesthesia, the tracheas were intubated randomly using either the Trachlight or the laryngoscope. Failure to intubate was defined as lack of successful intubation after three attempts. The duration of each attempt was recorded as the time from insertion of the device into the oropharynx to the time of its removal. The total time to intubation (TTI), an overall measure of the ease of intubation, was defined as the sum of the durations of all (as many as three) intubation attempts. Complications, such as mucosal bleeding, lacerations, dental injury, and sore throat, were recorded.

RESULTS

Nine hundred fifty patients (479 in the Trachlight group and 471 in the laryngoscope group) were studied. There was a 1% failure rate with the Trachlight, and 92% of intubations were successful on the first attempt, compared with a 3% failure rate and an 89% success rate on the first attempt with the laryngoscope (P not significant). All failures were followed by successful intubation using the alternate device. The TTI was significantly less with the Trachlight compared with the laryngoscope (15.7 +/- 10.8 vs. 19.6 +/- 23.7 s). For laryngoscopic intubation, the TTI was longer for patients with limited mandibular protrusion and mentohyoid distance, with a larger circumference of the neck, and with a high classification according to Mallampatti et al. However, there was no relation between the TTI and any of the airway parameters for Trachlight. There were significantly fewer traumatic events in the Trachlight group than in the laryngoscope group (10 vs. 37). More patients complained of sore throat in the laryngoscope group than in the Trachlight group (25.3% vs. 17.1%).

CONCLUSIONS

In contrast to laryngoscopy, the ease of intubation using the Trachlight does not appear to be influenced by anatomic variations of the upper airway. Intubation occasionally failed with the Trachlight but in all cases was resolved with direct laryngoscopy. The failures of direct laryngoscopy were resolved with Trachlight. Thus the combined technique was 100% successful in intubating the tracheas of all patients.

How does neurophysiological assessment influence the management and outcome of patients with carpal tunnel syndrome?

The objective of this study was to determine how neurophysiological assessment influenced the management and outcome of 100 consecutive patients referred to a department of clinical neurophysiology in a district general hospital with a provisional clinical diagnosis of carpal tunnel syndrome. Nerve conduction studies excluded the diagnosis in 36 patients who may have otherwise received inappropriate treatment. The decision whether to perform a carpal tunnel decompression was greatly influenced by a positive study. Symptoms subsequently resolved in 72-86% of patients treated on this basis, depending on the mode of treatment and the nerve conduction study findings, with similar outcomes for surgical and conservative measures. The clinical and estimated resource implications of this diagnostic service were found to be substantial.

Assessment of upper airway anatomy in awake, sedated and anaesthetised patients using magnetic resonance imaging

Magnetic Resonance Imaging was used to quantify the effects of 1. sedation and 2. general anaesthesia with a laryngeal mask airway (LMA) in place on the minimum antero-posterior (A-P) diameters of the naso-, oro- and hypopharynx and on the angle of the epiglottis relative to the adjacent posterior pharyngeal wall. Median sagittal T1-weighted images of the pharynx were obtained in 46 patients (16 awake, 14 sedated, 16 under general anaesthesia). In sedated patients, the A-P diameters of the pharynx were less than in awake patients, in particular at the levels of the epiglottis and soft palate. General anaesthesia and placement of a LMA was also associated with a reduced A-P diameter at the level of the soft palate, but with increased diameters at the levels of the tongue and epiglottis. Placement of a LMA caused abnormal downfolding of the epiglottis in most cases but this did not cause clinically significant airway obstruction.

Hepatic kinetics and magnetic resonance imaging of gadolinium ethoxybenzyl diethylenetriaminepentacetic acid (Gd-EOB-DTPA) in dogs

This complex study was designed to measure the transport and excretion characteristics of gadolinium ethoxybenzyl diethylenetriaminepentacetic acid (Gd-EOB-DTPA) in dog's livers following bolus and infusion. Simultaneous T1 magnetic resonance imaging was performed to measure maximum signal enhancement. Anaesthetized dogs had cannulation of the common bile duct and urinary bladder for collections and cannulation of the femoral artery and vein for monitoring, blood sampling and infusion. Gd-EOB-DTPA was administered by bolus (range 12.5-200 mumol/kg) and infusion (range 0.4-6.4 mumol/min per kg). An hepatic transport maximum 0.09-0.15 mumol/min/kg was achieved with a blood concentration of 0.03-0.06 mumol/mL. Marked hepatic affinity for Gd-EOB-DTPA was demonstrated with measurements of liver concentration. Maximum T1 signal enhancement was achieved with blood Gd-EOB-DTPA concentration of 0.02-0.03 mumol/mL and a liver concentration of 1-2 mumol/g. The transport maximum for Gd-EOB-DTPA in the dog was similar to that for ipodate and iodipamide and effective imaging was achieved with sub-maximal doses. The maximum signal enhancement at blood concentrations less than required for maximum transport suggest a wide latitude for effective clinical imaging.

The effect of magnetic resonance imaging in a teaching hospital on patient management

An observational study was undertaken to obtain measures of the impact of magnetic resonance imaging (MRI) on diagnosis, patient management and patient outcome. A minimum data set at the time of examination was used for 1119 consecutive patients referred by specialists for MRI of the brain or spine. Three month follow up of 707 brain examinations and 235 spinal examinations was undertaken using a questionnaire on diagnosis and patient management. Magnetic resonance imaging made a dominant contribution to final diagnoses of neoplasia and vascular disorders, but was less significant for white matter disease. In a high proportion of cases other types of examination also influenced the final diagnosis. Magnetic resonance imaging affected patient management in a high proportion of spinal examinations and in cases of cerebral neoplasm, with lesser contributions to cases of cerebrovascular disorder and white matter disease. While MRI was considered superior to other imaging methods, which it could often replace, in practice it will form only one input to the diagnostic decision.

A rodent model for testicular involvement in acute lymphoblastic leukaemia

The testis is the third common site of relapse after primary treatment of childhood acute lymphoblastic leukaemia, but in adults relatively few testicular relapses of acute lymphoblastic leukaemia have been reported. In the present investigation the differences in the behaviour of leukaemia in immature and mature rat testis and the interactions of testicular and leukaemic cells were studied. Intraperitoneal injection of rat T-leukaemic cells to sexually immature animals induced testicular infiltrations in 100% of animals in 17 days. The infiltrations were small and located perivascularly in the interstitial tissue. Intraperitoneal injection of T-leukaemic cells to sexually mature animals induced testicular infiltrates in 42% of the animals. Leukaemic cells injected directly to the lymph sinusoids of sexually immature and mature testis proliferated rapidly causing testicular enlargement. The M(r) > 5 K fraction of extracts of 50 days old normal rat testes inhibited 3H-TdR incorporation of both normal and leukaemic ConA-stimulated rat lymphoblasts significantly. The same fraction of extracts of testes of 25 days old rats did not have any effect on 3H-TdR incorporation. The normally occurring pubertal increase in the lymphocyte inhibitory effect of the M(r) > 5 K fraction of testis extracts on 3H-TdR incorporation of PBL was prevented following either intraperitoneal or intratesticular injection of rat leukaemic lymphoblasts administered at the age of 25 days. The present observations suggest that physiological pubertal changes in the permeability of vascular endothelium and immunosuppressive effect of the testis may be important explanatory factors for the smaller number of testicular relapses in men compared to boys seen after treatment of ALL.

Testins are structurally related to the mouse cysteine proteinase precursor but devoid of any protease/anti-protease activity

Testin I (M(r) 35,000) and testin II (M(r) 37,000) (testins) are two structurally and immunologically related testicular proteins that are actively synthesized and secreted by Sertoli cells. Treatment of adult rats with busulfan to destroy germ cells selectively in the testis could lead to a significant increase in the testicular testins level; as the germ cells reappeared in the testis, the testicular testins level declined and returned to the normal level. These observations indicated that the testicular content of testins in the rat is inversely correlated to the number of germ cells. When the partial N-terminal amino acid sequences for testin I and testin II were compared with the existing protein data base at Protein Identification Resource, it was noted that they displayed remarkable identity with CTLA-2 alpha and CTLA-2 beta, two novel molecules expressed in mouse activated T lymphocytes and mast cells, and the mouse cysteine proteinase proregion. When purified testins were assayed for the proteolytic and anti-protease activity using [14C]-casein, it was noted that it possessed neither proteolytic nor anti-protease activity, suggesting that it is not functioning as a protease and/or protease inhibitor in the testis.

Mycobacterium kansasii infection in the wrist and hand

Mycobacterium kansasii infection of the deep structures of the wrist and hand can cause progressive damage which may eventually lead to permanent loss of hand function. This report describes three cases followed by a review of the literature. The important principles of management in this unusual infection are discussed.

A new unit for long-stay psychiatric patients: organization, attitudes and quality of care

The present study describes and evaluates aspects of care in a new residential unit for chronic patients. The findings suggest that the unit is relatively resident-orientated in its management practices and that the staff are similarly orientated in their attitudes. Staff also hold generally optimistic attitudes to residents' potential accomplishments and consider themselves highly involved in decision-making. They also show high levels of positive interactions with the residents. Various aspects of staff attitudes and behaviour are positively correlated with seniority or length of time on the unit. The results are discussed in terms of the unit's organizational structure and its possible impact on residents' functioning.